Multifunctional viscosity index improver derived from amido-amine exhibiting improved low temperature viscometric properties

ABSTRACT

The present invention is directed to a viscosity index improver for lubricating oil compositions comprising the reaction product of A a copolymer of ethylene and at least one other alpha-olefin monomer, said copolymer grafted with ethylenically monoansaturataed carboxylic acid material and B amido-amine or thioamido-amine comprising the reaction product of a polyamine and alpha, beta-unsaturated compound of the formula ##STR1## wherein X is oxygen or sulfur, Y is OR 4 , --SR 4  or ##STR2## and R 1 , R 2 , R 3  R 4  and R 5  are independently selected from hydrogen, hydrocarbyl and substituted hydrocarbyl.

BACKGROUND OF THE INVENTION

The present invention relates to nitrogen containing grafted ethylenecopolymers useful as multi-functional viscosity index (V.I.) improveradditives, e.g., viscosity index improvers-dispersants, for oleaginouscompositions, particularly fuel oils and lubricating oils, methods forpreparing said grafted ethylene copolymers, and to oleaginouscompositions containing these nitrogen containing grafted copolymersMore specifically the instant invention relates to a copolymer ofethylene with other alpha-olefins as a backbone, said copolymercomprised of segmented copolymer chains with compositions which areintramolecularly heterogeneous and intermolecularly homogeneous, graftedwith ethylenically unsaturated carboxylic acid material and reacted withamido-amine. The additives of the instant invention provide oleaginouscompositions, particularly lubricating oil compositions, exhibitingimproved low temperature viscometric properties compared to conventionalnitrogen containing grafted ethylene-alpha-olefin copolymers.

The concept of derivatizing V.I. improving high molecular weightethylene and alpha-olefin copolymers with acid moieties such as maleicanhydride, followed by reaction with an amine or an amine and acarboxylic acid component to form a V.I.-dispersant oil additive isknown and is disclosed, inter alia, in the following patents:

U.S. Pat. No. 3,316,177 teaches ethylene copolymers such asethylene-propylene, or ethylene-propylene-diene, which are heated toelevated temperatures in the presence of oxygen so as to oxidize thepolymer and cause its reaction with maleic anhydride which is presentduring the oxidation The resulting polymer can then be reacted withalkylene polyamines.

U.S. Pat. No. 3,326,804 teaches reacting ethylene copolymers with oxygenor ozone, to form a hydroperoxidized polymer, which is grafted withmaleic anhydride followed by reaction with polyalkylene polyamines.

U.S Pat. No. 4,089,794 teaches grafting the ethylene copolymer withmaleic anhydride using peroxide in a lubricating oil solution, whereinthe grafting is preferably carried out under nitrogen, followed byreaction with polyamine.

U.S. Pat. No. 4,137,185 teaches reacting C₁ to C₃₀ mono carboxylic acidanhydrides, and dicarboxylic anhydrides, such as acetic anhydride,succinic anhydride, etc. with an ethylene copolymer reacted with maleicanhydride and a polyalkylene polyamine to inhibit cross linking andviscosity increase due to further reaction of any primary amine groupswhich were initially unreacted.

U.S. Pat. No. 4,144,181 is similar to U.S. Pat. No. 4,137,185 in that itteaches using a sulfonic acid to inactivate the remaining primary aminegroups when a maleic anhydride grafted ethylene-propylene copolymer isreacted with a polyamine.

U.S. Pat. No. 4,169,063 reacts an ethylene copolymer in the absence ofoxygen and chlorine at temperatures of 150° to 250° C. with maleicanhydride followed by reaction with polyamine.

A number of prior disclosures teach avoiding the use of polyamine havingtwo primary amine groups to thereby reduce cross-linking problems whichbecome more of a problem as the number of amine moieties added to thepolymer molecule is increased in order to increase dispersancy.

German Published Application No. P3025274 5 teaches an ethylenecopolymer reacted with maleic anhydride in oil using a long chain alkylhetero or oxygen containing amine.

U.S. Pat. No. 4,132,661 grafts ethylene copolymer, using peroxide and/orair blowing, with maleic anhydride and then reacts with primary-tertiarydiamine.

U.S. Pat. No. 4,160,739 teaches an ethylene copolymer which is grafted,using a free radical technique, with alternating maleic anhydride and asecond polymerizable monomer such as methacrylic acid, which materialsare reacted with an amine having a single primary, or a singlesecondary, amine group.

U.S. Pat. No. 4,171,273 reacts an ethylene copolymer with maleicanhydride in the presence of a free radical initiator and then withmixtures of C₄ to C₁₂ n-alcohol and amine such asN-aminopropylmorpholine or dimethylamino propyl amine to form aV.I.-dispersant-pour depressant additive.

U.S. Pat. No. 4,219,432 teaches maleic anhydride grafted ethylenecopolymer reacted with a mixture of an amine having only one primarygroup together with a second amine having two or more primary groups.

German published application No. 2753569.9 shows an ethylene copolymerreacted with maleic anhydride by a free-radical technique and thenreacted with an amine having a single primary group.

German published application No. 2845288 grafts maleic anhydride on anethylene-propylene copolymer by thermal grafting at high temperaturesand then reacts with amine having one primary group.

French published application No. 2423530 grafts maleic anhydride on anethylene-propylene copolymer with maleic anhydride at 150° to 210° C.followed by reaction with an amine having one primary or secondarygroup.

The early patents such as U.S. Pat. Nos. 3,316,177 and 3,326,804 taughtthe general concept of grafting an ethylene-propylene copolymer withmaleic anhydride and then reacting with a polyalkylene polyamine such aspolyethylene amines. Subsequently, U.S. Pat. No. 4,089,794 was directedto using an oil solution for free radical peroxide grafting the ethylenecopolymer with maleic anhydride and then reaction with the polyamineThis concept had the advantage that by using oil, the entire reactioncould be carried out in an oil solution to form an oil concentrate,which is the commercial form in which such additives are sold. This wasan advantage over using a volatile solvent for the reactions, which hasto be subsequently removed and replaced by oil to form a concentrate.Subsequently, in operating at higher polyamine levels in order tofurther increase the dispersing effect, increased problems occurred withthe unreacted amine groups cross-linking and thereby causing viscosityincrease of the oil concentrate during storage and subsequent formationof haze and in some instances gelling. Even though one or more moles ofthe ethylene polyamine was used per mole of maleic anhydride duringimide formation, cross-linking became more of a problem as the nitrogencontent of the polymers was increased. One solution was to use thepolyamines and then to react the remaining primary amino groups with anacid anhydride, preferably acetic anhydride, of U.S. Pat. No. 4,137,185or the sulfonic acid of U.S. Pat. No. 4,144,181. The cross-linkingproblem could also be minimized by avoidance of the ethylene polyaminesand instead using amines having one primary group which would react withthe maleic anhydride while the other amino groups would be tertiarygroups which were substantially unreactive. Patents or publishedapplications showing the use of such primary-tertiary amines noted aboveare U.S. Pat. No. 4,219,432, wherein a part of the polyamine wasreplaced with a primary-tertiary amine; U S. Pat. No. 4,132,661; U.S.Pat. No. 4,160,739; U.S. Pat. No. 4,171,273; German No. P2753569 9;German No. 2,845,288; and French No. 2,423,530.

U.S. Pat. Nos. 4,516,104 and 4,632,769 represented a further improvementover the art in that they permitted the utilization of the generallyless expensive polyamines having two primary amine groups, whileachieving good dispersancy levels, inhibiting cross-linking and allowinginitiator, e.g., peroxide, grafting in oil.

U.S. Pat. No. 4,517,104 discloses polymeric viscosity index (V.I )improver-dispersant additives for petroleum oils, particularlylubricating oils, comprising a copolymer of ethylene with one or more C₃to C₂₈ alpha-olefins, preferably propylene, which have been grafted withacid moieties, e.g., maleic anhydride, preferably using a free radicalinitiator in a solvent, preferably lubricating oil, and then reactedwith a mixture of a carboxylic acid component, preferably an alkylsuccinic anhydride, and a polyamine having two or more primary aminegroups. Or the grafted polymer may be reacted with said acid componentprereacted with said polyamine to form salts, amides, imides, etc. andthen reacted with said grafted olefin polymer. These reactions canpermit the incorporation of varnish inhibition and dispersancy into theethylene copolymer while inhibiting cross-linking or gelling.

U.S. Pat. No. 4,632,769 discloses oil soluble viscosity improvingethylene copolymers such as copolymers of ethylene and propylene,reacted or grafted with ethylenically unsaturated carboxylic acidmoieties, preferably maleic anhydride moieties, and then reacted withpolyamines having two or more primary amine groups and a C₂₂ to C₂₈olefin carboxylic acid component, preferably alkylene polyamine andalkenyl succinic anhydride, respectively. These reactions can permit theincorporation of varnish inhibition and dispersancy into the ethylenecopolymer while inhibiting cross-linking or gelling.

While the additives disclosed in U.S. Pat. Nos. 4,517,104 and 4,632,769provide quite useful oil compositions there is a need for oilcompositions which exhibit better low temperature viscometric propertiesthan those possessed by conventional oil compositions.

U.S. Pat. No. 2,921,085 relates to the preparation ofbeta-aminopropionamides by reaction of an alkyl amine with an acrylateto form an alkyl aminopropionate and reaction of the latter compoundwith an amine The resulting compounds are disclosed to have utility assurface active agents, specifically as emulsifying, wetting, foaming anddetergent agents.

U.S. Pat. No. 3,337,609 relates to adducts of hydroxyalkyl alkylenepolyamines and acrylates. The resulting adducts are added topolyepoxides to provide compositions which are suitable for use as abarrier coating for polyethylene surfaces, and for additional end uses,such as in molding. In addition, the adducts are disclosed to be usefulas catalysts in resin preparation and as corrosion inhibitors in watersystems for ferrous metals.

U.S. Pat. No. 3,417,140 relates to the preparation of amido-aminecompositions, which are useful as epoxy resin curing agents, by reactinga polyalkylene polyamine and a fatty amine (comprising a mono- ordiamine having as one of the substituents on a nitrogen atom ahydrocarbyl radical having 8 to 24 carbon atoms) with an alpha-betaunsaturated carbonylic compound. It is disclosed that this reactionoccurs through the Michael addition of an amine group across theunsaturated group of the carbonylic compound and through thecondensation of an amine group with the carbonylic group.

U.S. Pat. No. 3,247,163 also relates to curing agents for polyepoxidecompositions, which curing agents are prepared by reacting an organicamine and an acrylate.

U.S. Pat. No. 3,445,441 relates to amino-amine polymers characterized bybeing a reaction product of at least a polyamine and an acrylate typecompound, such as methyl or ethyl acrylate, and methyl or ethylmethacrylate The patent states that the polymers are useful in a widevariety of applications, such as floculating agents, water clarifyingadditives, corrosion inhibitors in oil and gas wells, and as lube oiladditives. The patent further discloses that the polymers may bederivitized, including acylation with monocarboxylic acids andpolycarboxylic acids, aliphatic dicarboxylic acids, aromaticdicarboxylic acids, for example, diglycolic, phthalic, succinic, etc.,acids.

U.S. Pat. No. 3,903,003 relates to lubricating compositions containingan amido-amine reaction product of a terminally carboxylated isoprenepolymer which is formed by reacting a terminally carboxylatedsubstantially completely hydrogenated polyisoprene having an averagemolecular weight between about 20,000 and 250,000 and a nitrogencompound of the group consisting of polyalkylene amines and hydroxylpolyalkylene amines.

U.S. Pat. No. 4,493,771 relates to scale inhibiting with compoundscontaining quaternary ammonium and methylene phosphonic acid groups.These compounds are derivatives of polyamines in which the aminehydrogens have been substituted with both methylene phosphonic acidgroups or their salts and hydroxypropyl quaternary ammonium halidegroups. The patent discloses that any amine that contains reactive aminohydrogens can be utilized, for example, polyglycol amines, amido-amines,oxyacylated amines, and others.

U.S. Pat. No. 4,459,241 contains a similar disclosure to U.S. Pat. No.4,493,771.

The problem of providing V.I. oil additives exhibiting improved lowtemperature viscometric properties is addressed in U.S. Pat. No.4,804,794, which is incorporated herein by reference. U.S. Pat. No.4,804,794 discloses segmented copolymers of ethylene and at least oneother alpha-olefin monomer, each copolymer being intramolecularlyheterogeneous and intermolecularly homogeneous and at least one segmentof the copolymer, constituting at least 10% of the copolymer's chain,being a crystallizable segment. These copolymers are disclosed asexhibiting good mechanical properties such as good shear stability andas being useful V.I. improvers which provide lubricating oils havinghighly desirable viscosity and pumpability properties at lowtemperatures. However, these copolymers are disclosed as being V.I.improvers, and there is no disclosure of grafting said copolymers withan ethylenically unsaturated carboxylic acid material and thereafterreacting these grafted copolymers with amido-amines to providemultifunctional viscosity index improver additives, e.g., viscosityindex improver-dispersant additives, for oleaginous compositions.Indeed, it was heretofore generally believed that these ethylenecopolymers could not be grafted with conventional ethylenicallyunsaturated grafting materials and thereafter reacted with nitrogencontaining compounds such as polyamines without substantiallydeleteriously or adversely affecting, i.e., broadening, the narrowmolecular weight distribution (MWD). It was believed that thisdeleterious effect upon the narrow MWD would have a concomitantdeleterious effect upon the intermolecular homogeneity, microstructure(intramolecular heterogeneity), and, therefore, upon the advantageouslow temperature viscometric properties. It has been surprisinglydiscovered that oleaginous compositions containing ethylene copolymersgrafted with ethylenically monounsaturated carboxylic acid material andreacted with an amido-amine to form nitrogen containing grafted ethylenecopolymers exhibit better low temperature viscometric properties thanthose containing conventional nitrogen containing grafted ethylenecopolymers. Thus, the multifunctional viscosity index improver additivesof the instant invention provide oleaginous compositions, particularlylubricating oil compositions, exhibiting dispersancy and better lowtemperature viscometric characteristics than conventionalmultifunctional viscosity index improvers comprised of nitrogen or estercontaining grafted conventional ethylene copolymers.

SUMMARY OF THE INVENTION

The present invention is directed to oil soluble nitrogen containinggrafted ethylene copolymers useful as multifunctional viscosity indeximprovers or modifiers, e.g., as V.I. improver-dispersant additives, inoleaginous compositions. The nitrogen containing grafted ethylenecopolymers of the instant invention provide oleaginous compositions, inparticular lubricating oil compositions, exhibiting improved viscometricproperties, particularly highly desirable viscosity properties at lowtemperatures, and dispersancy characteristics.

The ethylene copolymers of the instant invention are grafted with anethylenically mono-unsaturated carboxylic acid grafting material and thegrafted ethylene copolymers are then reacted with at least oneamido-amine.

The amido-amine is characterized by being a reaction product of at leastone amine and an α-, β-unsaturated compound of the formula ##STR3##wherein X is sulfur or oxygen, Y is --OR⁴, --SR⁴, or --NR⁴ (R⁵), and R¹,R², R³, R⁴ and R⁵ are the same or different and are hydrogen orsubstituted or unsubstituted hydrocarbyl.

The copolymers which are grafted and reacted with the amido-amine aredisclosed in U.S. Pat. No. 4,804,794, which is incorporated herein byreference. These copolymers are segmented copolymers of ethylene and atleast one other alpha-olefin monomer; each copolymer is intramolecularlyheterogeneous and intermolecularly homogeneous and at least one segmentof the copolymer, constituting at least 10% of the copolymer's chain, isa crystallizable segment. For the purposes of this application, the term"crystallizable segment" is defined to be each segment of the copolymerchain having a number-average molecular weight of at least 700 whereinthe ethylene content is at least 57 wt.%. The remaining segments of thecopolymer chain are herein termed the "low crystallinity segments" andare characterized by an average ethylene content of not greater thanabout 53 wt %. Furthermore, the molecular weight distribution (MWD) ofcopolymer is very narrow. It is well known that the breadth of themolecular weight distribution can be characterized by the ratios ofvarious molecular weight averages. For example, an indication of anarrow MWD in accordance with the present invention is that the ratio ofweight to number-average molecular weight (M_(w) /M_(n)) is less than 2.Alternatively, a ratio of the z-average molecular weight toweight-average molecular weight (M.sub. z /M_(w)) of less than 1.8typifies a narrow MWD in accordance with the present invention. It isknown that a portion of the property advantages of copolymers inaccordance with the present invention are related to these ratios. Smallweight fractions of material can disproportionately influence theseratios while not significantly altering the property advantages whichdepend on them. For instance, the presence of a small weight fraction(e.g. 2%) of low molecular weight copolymer can depress M_(n), andthereby raise M_(w) /M_(n) above 2 while maintaining M_(z) /M_(w) lessthan 1.8. Therefore, the copolymer reactants, in accordance with thepresent invention, are characterized by having at least one of M_(w)/M_(n) less than 2 and M_(z) /M_(w) less than 1.8. The copolymerreactant comprises chains within which the ratio of the monomers variesalong the chain length. To obtain the intramolecular compositionalheterogeneity and narrow MWD, the ethylene copolymer reactants arepreferably made in a tubular reactor.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the instant invention there are provided nitrogencontaining polymeric materials useful as multifunctional viscosity indeximprovers, particularly viscosity index improver-dispersant additives,for oleaginous materials, particularly lubricating oils, which arecomprised of (i) certain specific types of ethylene and alpha-olefincopolymers grafted with (ii) ethylenically monounsaturated carboxylicacid material, and (iii) reacted with amido-amine.

More particularly, in one aspect of the instant invention, hereinafterreferred to as Aspect A these polymeric materials are comprised of thereaction products of:

(i) backbone copolymer of ethylene and at least one other alpha-olefinmonomer, said copolymer comprising intramolecularly heterogeneous andintermolecularly homogeneous copolymer chains containing at least onecrystallizable segment of methylene units and at least one lowcrystallinity ethylene-alpha-olefin copolymer segment, wherein said atleast one crystallizable segment comprises at least about 10 weightpercent of said copolymer chain and contains at least about 57 weightpercent ethylene, wherein said low crystallinity segment contains notgreater than about 53 weight percent ethylene, and wherein saidcopolymer has a molecular weight distribution characterized by at leastone of a ratio of M_(w) /M_(n) of less than 2 and a ratio of M_(z)/M_(w) of less than 1.8, and wherein at least two portions of anindividual intramolecularly heterogeneous chain, each portion comprisingat least 5 weight percent of said chain, differ in composition from oneanother by at least 7 weight percent ethylene; grafted withethylenically monounsaturated carboxylic acid material; and

(ii) amido-amine.

In another aspect of the instant invention, hereinafter referred to asAspect B, the nitrogen containing grafted ethylene copolymers arecomprised of the reaction products of:

(i) backbone copolymer of ethylene and at least one other alpha-olefinmonomer, said copolymer comprising intramolecularly heterogeneous andintermolecularly homogeneous copolymer chains containing at least onecrystallizable segment of methylene units and at least one lowcrystallinity ethylene-alpha-olefi copolymer segment, wherein said atleast one crystallizable segment comprises at least about 10 weightpercent of said copolymer chain and contains at least about 57 weightpercent ethylene, wherein said low crystallinity segment contains notgreater than about 53 weight percent ethylene, and wherein saidcopolymer has a molecular weight distribution characterized by at leastone of a ratio of M_(w) /M_(n) of less than 2 and a ratio of M_(z)/M_(w) of less than 1.8, and wherein at least two portions of anindividual intramolecularly heterogeneous chain, each portion comprisingat least 5 weight percent of said chain, differ incomposition from oneanother by at least 7 weight percent ethylene; granted withethylenically monounsaturated carboxylic acid material;

(ii) carboxylic acid component comprising C₁₂ -C₄₉ hydrocarbylsubstituted dicarboxylic acid or anhdride, C₅₀ -C₄₀₀ hydrocarbylsubstituted monocarboxylic acid, or C₅₀ -C₄₀₀ hydrocarbyl substituteddicarboxylic acid, or anhydride; and

(iii) amido-amine.

In yet a further aspect of the instant invention the nitrogen containingcarboxylic acid material grafted ethylene copolymers of either aspect Aor B are reacted or post-treated with a viscosity stabilizing or endcapping agent such as, for example, a C₁₂ -C₁₈ hydrocarbyl substituteddicarboxylic anhydride.

When the nitrogen containing grafted ethylene copolymers of the instantinvention are incorporated into oleaginous materials such as lubricatingoils the resultant oleaginous compositions exhibit better lowtemperature viscometric properties than oleaginous compositionscontaining conventional nitrogen containing grafted ethylene copolymers.Furthermore, the nitrogen containing grafted ethylene copolymers of thisinvention function as dispersants in oleaginous compositions andgenerally exhibit substantially similar or better dispersancy efficacyas conventional nitrogen containing grafted ethylene copolymers fallingoutside the scope of the instant invention.

Ethylene and Alpha-Olefin Copolymer

The ethylene and alpha-olefin copolymers defined as (i) hereinafore arecopolymers of ethylene with at least one other alpha-olefin comprised ofsegmented copolymer chains with compositions which are intramolecularlyheterogeneous and intermolecularly homogeneous.

For convenience, certain terms that are repeated throughout the presentspecification are defined below:

a. Inter-CD defines the compositional variation, in terms of ethylenecontent, among polymer chains. It is expressed as the minimum deviation(analogous to a standard deviation) in terms of weight percent ethylene,from the average ethylene composition for a given copolymer sampleneeded to include a given weight percent of the total copolymer sample,which is obtained by excluding equal weight fractions from both ends ofthe distribution. The deviation need not be symmetrical. When expressedas a single number, for example 15% Inter-CD, it shall mean the largerof the positive or negative deviations. For example, for a Gaussiancompositional distribution, 95.5% of the polymer is within 20 wt.%ethylene of the mean if the standard deviation is 10%. The Inter-CD for95.5 wt. % of the polymer is 20 wt. % ethylene for such a sample.

b. Intra-CD is the compositional variation, in terms of ethylene, withina copolymer chain. It is expressed as the minimum difference in weight(wt. %) ethylene that exists between two portions of a single copolymerchain, each portion comprising at least 5 weight % of the chain.

c. Molecular weight distribution (MWD) is a measure of the range ofmolecular weights within a given copolymer sample. It is characterizedin terms of at least one of the ratios of weight-average tonumber-average molecular weight, M_(w) /M_(n), and z-average toweight-average molecular weight, M_(z) /M_(w), where: ##EQU1## whereinN_(i) is the number of molecules of molecular weight M_(i).

d. Viscosity Index (V.I.) is the ability of a lubricating oil toaccommodate increases in temperature with a minimum decrease inviscosity. The greater this ability, the higher the V.I. Viscosity Indexis determined according to ASTM D2270.

The instant copolymers are segmented copolymers of ethylene and at leastone other alpha-olefin monomer wherein the copolymer's chain contains atleast one crystallizable segment of ethylene monomer units, as will bemore completely described below, and at least one low crystallinityethylene-alpha-olefin copolymer segment, where in the low crystallinitycopolymer segment is characterized in the unoriented bulk state after atleast 24 hours annealing by a degree of crystallinity of less than about0.2% at 23° C., and wherein the copolymer's chain is intramolecularlyheterogeneous and intermolecularly homogeneous, and has an MWDcharacterized by at least one of M_(w) /M_(n) of less than 2 and M_(z)/M_(w) of less than 1.8. The crystallizable segments comprise from about10 to 90 wt. %, preferably from about 20 to 85 wt. %, of the totalcopolymer chain, and contain an average ethylene content which is atleast about 57 wt. %, preferably at least about 62 wt. %, and morepreferably at least about 63 wt. % and which is not greater than 95 wt.%, more preferably <85%, and most preferably <75 wt. % (e.g., from about58 to 68 wt. %). The low crystallinity copolymer segments comprise fromabout 90 to 10 wt. %, preferably from about 80 to 15 wt. %, and morepreferably from about 65 to 35 wt. %, of the total copolymer chain, andcontain an average ethylene content of from about 20 to 53 wt. %,preferably from about 30 to 50 wt. %, and more preferably from about 35to 50 wt. %. The copolymers comprise intramolecularly heterogeneouschain segments wherein at least two portions of an individualintramolecularly heterogeneous chain, each portion comprising at least 5weight percent of the chain and having a molecular weight of at least7000 contain at least 5 wt. % ethylene and differ in composition fromone another by at least 5 weight percent ethylene, wherein theintermolecular compositional dispersity of the polymer is such that 95wt. % of the polymer chains have a composition 15% or less different inethylene from the average weight percent ethylene composition, andwherein the copolymer is characterized by at least one or a ratio ofM_(w) /M_(n) of less than 2 and a ratio of M_(z) /M_(w) of less than1.8.

As described above, the copolymers will contain at least onecrystallizable segment rich in methylene units (hereinafter called an"M" segment) and at least one low crystallinity ethylene-alpha-olefincopolymer segment (hereinafter called a "T" segment). The copolymers maybe therefore illustrated by copolymers selected from the groupconsisting of copolymer chain structures having the following segmentsequences:

    M-T,                                                       (I)

    T.sup.1 -(M-T.sup.2)x, and                                 (II)

    T.sup.1 -(M.sup.1 -T.sup.2)y-M.sup.2                       (III)

wherein M and T are defined above, M¹ and M² can be the same ordifferent and are each M segments, T¹ and T² can be the same ordifferent and are each T segments, x is an integer of from 1 to 3 and yis an integer of 1 to 3.

In structure II (x=1), the copolymer's M segment is positioned betweentwo T segments, and the M segment can be positioned substantially in thecenter of the polymer chain (that is, the T¹ and T² segments can besubstantially the same molecular weight and the sum of the molecularweight of the T¹ and T² segments can be substantially equal to themolecular weight of the M segment), although this is not essential tothe practice of this invention. Preferably, the copolymer will containonly one M segment per chain. Therefore, structures I and II (x=1) arepreferred.

Preferably, the M segments and T segments of the copolymer are locatedalong the copolymer chain so that only a limited number of the copolymerchains can associate before the steric problems associated with packingthe low crystallinity T segments prevents further agglomeration.Therefore, in a preferred embodiment, the M segment is located near thecenter of the copolymer chain and only one M segment is in the chain.

As will be shown below, a copolymer of the structure

    M.sup.1 -(T-M.sup.2).sub.z                                 (IV)

(wherein M¹, M² and T are as defined above, and wherein z is an integerof at least 1) are undesirable as viscosity modifier polymers. It hasbeen found that solutions of structure IV copolymers in oil tend to geleven when the M and T portions have exactly the same composition andmolecular weight as structure II copolymers (with x=z=1). It is believedthis poor viscosity modifier performance is due to the inability of acenter T segment to sterically stabilize against association.

The M segments of the copolymers of this invention comprise ethylene andcan also comprise at least one other alpha-olefin, e.g., containing 3 to18 carbon atoms. The T segments comprise ethylene and at least one otheralpha-olefin, e.g., alpha-olefins containing 3 to 18 carbon atoms. The Mand T segments can also comprise other polymerizable monomers, e.g.,non-conjugated dienes or cyclic mono-olefins.

Since the present invention is considered to be most preferred in thecontext of ethylene-propylene (EPM) copolymers it will be described indetail in the context of EPM.

Copolymer (i)(a) in accordance with the present invention is preferablymade in a tubular reactor. When produced in a tubular reactor withmonomer feed only at the tube inlet, it is known at the beginning of thetubular reactor, ethylene, due to its high reactivity , will bepreferentially polymerized. The concentration of monomers in solutionchanges along the tube in favor of propylene as the ethylene isdepleted. The result, with monomer feed only at the inlet, is copolymerchains which are higher in ethylene concentration in the chain segmentsgrown near the reactor inlet (as defined at the point at which thepolymerization reaction commences), and higher in propyleneconcentration in the chain segments formed near the reactor outlet.These copolymer chains are therefore tapered in composition. Anillustrative copolymer chain of ethylene-propylene is schematicallypresented below with E representing ethylene constituents and Prepresenting propylene constituents in the chain: ##STR4##

As can be seen from this illustrative schematic chain, the far left-handsegment (1) thereof represents that portion of the chain formed at thereactor inlet where the reaction mixture is proportionately richer inthe more reactive constituent ethylene. This segment comprises fourethylene molecules and one propylene molecule. However, as subsequentsegments are formed from left to right with the more reactive ethylenebeing depleted and the reaction mixture proportionately increasing inpropylene concentration, the subsequent chain segments become moreconcentrated in propylene. The resulting chain is intra-molecularlyheterogeneous.

The property, of the copolymer discussed herein, related tointramolecular compositional dispersity (compositional variation withina chain) shall be referred to as Intra-CD, and that related tointermolecular compositional dispersity (compositional variation betweenchains) shall be referred to as Inter-CD.

For copolymers in accordance with the present invention, composition canvary between chains as well as along the length of the chain. An objectof this invention is to minimize the amount of inter-chain variation.The Inter-CD can be characterized by the difference in compositionbetween the copolymer fractions containing the highest and lowestquantity of ethylene. Techniques for measuring the breadth of theInter-CD are known as illustrated in "Polymerization of ethylene andpropylene to amorphous copolymers with catalysts of vanadium oxychlorideand alkyl aluminum halides"; E. Junghanns, A. Gumboldt and G. Bier;Makromol. Chem., V. 58 (12/12/62): 18-42, wherein ap-xylene/dimethylformamide solvent/non-solvent was used to fractionatecopolymer into fractions of differing intermolecular composition. Othersolvent/non-solvent systems can be used as hexane/2 propanol, as will bediscussed in more detail below.

The Inter-CD of copolymer in accordance with the present invention issuch that 95 wt. % of the copolymer chains have an ethylene compositionthat differs from the average weight percent ethylene composition by 15wt. % or less. The preferred Inter-CD is about 13% or less, with themost preferred being about 10% or less. In comparison, Junghanns et al.found that their tubular reactor copolymer had an Inter-CD of greaterthan 15 wt. %.

Broadly, the Intra-CD of copolymer in accordance with the presentinvention is such that at least two portions of an individualintramolecularly heterogeneous chain, each portion comprising at least 5weight percent of the chain, differ in composition from one another byat least 7 weight percent ethylene. Unless otherwise indicated, thisproperty of Intra-CD as referred to herein is based upon at least two 5weight percent portions of copolymer chain. The Intra-CD of copolymer inaccordance with the present invention can be such that at least twoportions of copolymer chain differ by at least 10 weight percentethylene. Differences of at least 20 weight percent, as well as, of atleast 40 weight percent ethylene are also considered to be in accordancewith the present invention.

The experimental procedure for determining Intra-CD is as follows. Firstthe Inter-CD is established as described below, then the polymer chainis broken into fragments along its contour and the Inter-CD of thefragments is determined. The difference in the two results is due toIntra-CD as can be seen in the illustrative example below.

Consider a heterogeneous sample polymer containing 30 monomer units. Itconsists of 3 molecules designated A, B, C.

    ______________________________________                                        A       EEEEPEEEPEEEPPEEPPEPPPEPPPPPPP                                        B       EEEEEPEEEPEEEPPEEEPPPEPPPEEPPP                                        C       EEPEEEPEEEPEEEPEEEPPEEPPPEEPPP                                        ______________________________________                                    

Molecule A is 36.8 wt. % ethylene, B is 46.6%, and C is 50% ethylene.The average ethylene content for the mixture is 44.3%. For this samplethe Inter-CD is such that the highest ethylene polymer contains 5.7%more ethylene than the average while the lowest ethylene content polymercontains 7.5% less ethylene than the average. Or, in other words, 100weight % of the polymer is within +5.7% and -7.5% ethylene about anaverage of 44.3%. Accordingly, the Inter-CD is 7.5% when the givenweight % of the polymer is 100%.

If the chains are broken into fragments, there will be a new Inter-CD.For simplicity, consider first breaking only molecule A into fragmentsshown by the slashes as follows:

    EEEEP/EEEPE/EEPPE/EPPEP/PPEPP/PPPPP

Portions of 72.7%, 72.7%, 50%, 30.8%, 14.3% and 0% ethylene areobtained. If molecules B and C are similarly broken and the weightfractions of similar composition are grouped a new Inter-CD is obtained.

In order to determine the fraction of a polymer which isintramolecularly heterogeneous in a mixture of polymers combined fromseveral sources the mixture must be separated into fractions which showno further heterogenity upon subsequent fractionation. These fractionsare subsequently fractured and fractionated to reveal which areheterogeneous.

The fragments into which the original polymer is broken should be largeenough to avoid end effects and to give a reasonable opportunity for thenormal statistical distribution of segments to form over a given monomerconversion range in the polymerization. Intervals of ca 5 weight % ofthe polymer are convenient. For example, at an average polymer molecularweight of about 105, fragments of ca 5000 molecular weight areappropriate. A detailed mathematical analysis of plug flow or batchpolymerization indicates that the rate of change of composition alongthe polymer chain contour will be most severe at high ethyleneconversion near the end of the polymerization. The shortest fragmentsare needed here to show the low ethylene content sections.

The best available technique for determination of compositionaldispersity for non-polar polymers is solvent/non-solvent fractionationwhich is based on the thermodynamics of phase separation. This techniqueis described in "Polymer Fractionation", M. Cantow editor, Academic1967, p. 341 and in H. Inagaki, T. Tanaku, "Developments in PolymerCharacterization", 3, 1, (1982). These are incorporated herein byreference.

For non-crystalline copolymers of ethylene and propylene, molecularweight governs insolubility more than does composition in asolvent/non-solvent solution. High molecular weight polymer is lesssoluble in a given solvent mix. Also, there is a systematic correlationof molecular weight with ethylene content for the polymers describedherein. Since ethylene polymerizes much more rapidly than propylene,high ethylene polymer also tends to be high in molecular weight.Additionally, chains rich in ethylene tend to be less soluble inhydrocarbon/polar non-solvent mixtures than propylene-rich chains.Furthermore, for crystalline segments, solubility is significantlyreduced. Thus, the high molecular weight, high ethylene chains areeasily separated on the basis of thermodynamics.

A fractionation procedure is as follows: Unfragmented polymer isdissolved in n-hexane at 23° C. to form ca a 1% solution (1 g.polymer/100 cc hexane). Isopropyl alcohol is titrated into the solutionuntil turbidity appears at which time the precipitate is allowed tosettle. The supernatant liquid is removed and the precipitate is driedby pressing between Mylar® polyethylene terphthalate) film at 150.C.Ethylene content is determined by ASTM method D-3900. Titration isresumed and subsequent fractions are recovered and analyzed until 100%of the polymer is collected. The titrations are ideally controlled toproduce fractions of 5-10% by weight of the original polymer, especiallyat the extremes of composition.

To demonstrate the breadth of the distribution, the data are plotted as% ethylene versus the cumulative weight of polymer as defined by the sumof half the weight % of the fraction of that composition plus the totalweight % of the previously collected fractions.

Another portion of the original polymer is broken into fragments. Asuitable method for doing this is by thermal degradation according tothe following procedure: In a sealed container in a nitrogen-purgedoven, a 2mm thick layer of the polymer is heated for 60 minutes at 330°C. (The time or temperature can be empirically adjusted based on theethylene content and molecular weight of the polymer. This should beadequate to reduce a 105 molecular weight polymer to fragments of ca5000 molecular weight. Such degradation does not substantially changethe average ethylene content of the polymer, although propylene tends tobe lost on scission in preference to ethylene. This polymer isfractionated by the same procedure as the high molecular weightprecursor. Ethylene content is measured, as well as molecular weight onselected fractions.

The procedure to characterize intramolecular heterogeneity is laboriousand even when performed at an absolute optimum, does not show how thesegments of the chain are connected. In fact it is not possible, withcurrent technology, to determine the polymer structure without recourseto the synthesis conditions. With knowledge of the synthesis conditions,the structure can be defined as follows.

Ethylene, propylene or high alpha-olefin polymerizations with transitionmetal catalysts can be described by the terminal copolymerization model,to an approximation adequate for the present purpose. (G. Ver Strate,Encyclopedia of Polymer Science and Engineering, vol. 6, 522 (1986)). Inthis model, the relative reactivity of the two monomers is specified bytwo reactivity ratios defined as follows: ##EQU2## Given these twoconstants, at a given temperature, the ratio of the molar amount ofethylene, E, to the molar amount of propylene, P, entering the chainfrom a solution containing ethylene and propylene at molarconcentrations [E] and [P] respectively is ##EQU3##

The relation of E and P to the weight % ethylene in the polymer is asfollows ##EQU4##

The values of R₁ and R₂ are dependent on the particular comonomer andcatalyst employed to prepare the polymer, the polymerization temperatureand, to some extent, the solvent.

For all transition metal catalysts specified herein, R₁ is significantlylarger than R₂. Thus, as can be seen from equation (1), ethylene will beconsumed more rapidly than propylene for a given fraction of the monomerin the reacting medium. Thus, the ratio of [E]/[P] will decrease as themonomers are consumed. Only if R₁ =R₂ will the composition in thepolymer equal that in the reacting medium.

If the amount of monomer that has reacted at a given time in a batchreactor or at a given point in a tubular reactor can be determined, itis possible through equation (1), to determine the instantaneouscomposition being formed at a given point along the polymer chain.Demonstration of narrow MWD and increasing MW along the tube proves thecompositional distribution is intramolecular. The amount of polymerformed can be determined in either of two ways. Samples of thepolymerizing solution may be collected, with appropriate quenching toterminate the reaction at various points along the reactor, and theamount of polymer formed evaluated. Alternatively, if the polymerizationis run adiabatically and the heat of polymerization is known, the amountof monomer converted may be calculated from the reactor temperatureprofile.

Finally, if the average composition of the polymer is measured at aseries of locations along the tube, or at various times in the batchpolymerization case, it is possible to calculate the instantaneouscomposition of the polymer being made. This technique does not requireknowledge of R₁ and R₂ or the heat of polymerization, but it doesrequire access to the polymer synthesis step.

All of these methods have been employed with consistent results.

For the purpose of this patent, R₁ and R₂ thus simply serve tocharacterize the polymer composition in terms of the polymerizationconditions. By defining R₁ and R₂, we are able to specify theintramolecular compositional distribution. In the examples shown belowwhere VCl₄ and ethylaluminum sesquichloride are employed in hexane assolvent, R₁ =1.8 exp(+500/RT_(k)) and R₂ =3.2 exp(-1500/RT_(k)). Where"R" is the gas constant (1.98) col/deg-mole) and "T_(k) " is degreesKelvin. For reference, at 20° C. R₁ =9.7, R₂ =0.02.

The R₁ and R₂ given above predict the correct final average polymercomposition. If the R₁ and R₂ and expression (2) are someday proven tobe inaccurate the polymer intramolecular compositional distribution willremain as defined herein in terms of the polymerization conditions butmay have to be modified on the absolute composition scales. There islittle likelihood that they are in error by more than a few percent,however.

Ethylene content is measured by ASTM-D3900 for ethylene-propylenecopolymers between 35 and 85 wt. % ethylene. Above 85% ASTM-D2238 can beused to obtain methyl group concentrations which are related to percentethylene in an unambiguous manner for ethylene-propylene copolymers.When comonomers other than propylene are employed no ASTM tests coveringa wide range of ethylene contents are available; however, proton andcarbon-13 nuclear magnetic reasonance spectroscopy can be employed todetermine the composition of such polymers. These are absolutetechniques requiring no calibration when operated such that all nucleiiof a given element contribute equally to the spectra. For ranges notcovered by the ASTM tests for ethylene-propylene copolymers, thesenuclear magnetic resonance methods can also be used.

Molecular weight and molecular weight distribution are measured using aWaters 150C gel permeation chromatography equipped with a ChromatixKMX-6 (LDC-Milton Roy, Riviera Beach, Fla.) on-line light scatteringphotometer. The system is used at 135° C. with 1,2,4 trichlorobenzene asmobile phase. Showdex (Showa-Denko America, Inc.) polystyrene gelcolumns 802, 803, 804 and 805 are used. This technique is discussed in"Liquid Chromatography of Polymers and Related Materials III", J. Cazeseditor. Marcel Dekker, 1981, p. 207 (incorporated herein by reference).No corrections for column spreading are employed; however, data ongenerally accepted standards, e.g., National Bureau of StandardsPolyethene 1484 and anionically produced hydrogenated polyisoprenes (analternating ethylene-propylene copolymer) demonstrate that suchcorrections on M_(w) /M_(n) or M_(z) /M_(w) are less than .05 unit.M_(w) /M_(n) is calculated from an elution time-molecular weightrelationship whereas M_(z) /M_(w) is evaluated using the lightscattering photometer. The numerical analyses can be performed using thecommercially available computer software GPC2, MOLWT2 available fromLDC/Milton Roy-Riviera Beach, Fla.

As already noted, copolymers in accordance with the present inventionare comprised of ethylene and at least one other alpha-olefin. It isbelieved that such alpha-olefins could include those containing 3 to 18carbon atoms, e.g., propylene, butene-1, pentene-1, etc. Alpha-olefinsof 3 to 6 carbons are preferred due to economic considerations. The mostpreferred copolymers in accordance with the present invention are thosecomprised of ethylene and propylene.

As is well known to those skilled in the art, copolymers of ethylene andhigher alpha-olefins such as propylene often include other polymerizablemonomers. Typical of these other monomers may be non-conjugated dienessuch as the following non-limiting examples:

a. straight chain acyclic dienes such as: 1,4-hexadiene; 1,6-octadiene;

b. branched chain acyclic dienes such as: 5-methyl-1, 4-hexadiene; 3,7-dimethyl-1,6-octadiene; 3, 7-dimethyl-1,7-octadiene and the mixedisomers of dihydro-myrcene and dihydroocinene;

c. single ring alicyclic dienes such as: 1, 4-cyclohexadiene;1,5-cyclooctadiene; and 1,5-cyclododecadiene;

d. multi-ring alicyclic fused and bridged ring dienes such as:tetrahydroindene; methyltetrahydroindene; dicyclopentadiene;bicyclo-(2,2,1)-hepta-2, 5-diene; alkenyl, alkylidene, cycloalkenyl andcycloalkylidene norbornenes such as 5-methylene-2-norbornene (MNB),5-ethylidene-2-norbornene (ENB), 5-propylene-2-norbornene,5-isopropylidene-2-norbornene, 5-(4-cyclopentenyl)-2-norbornene;5-cyclohexylidene-2-norbornene.

Of the non-conjugated dienes typically used to prepare these copolymers,dienes containing at least one of the double bonds in a strained ringare preferred. The most preferred diene is 5-ethylidene-2-norbornene(ENB). The amount of diene (wt. basis) in the copolymer could be fromabout 0% to 20% with 0% to 15% being preferred. The most preferred rangeis 0% to 10%.

As already noted, the most preferred copolymer in accordance with thepresent invention is ethylene-propylene. The average ethylene content ofthe copolymer could be as low as about 20% on a weight basis. Thepreferred minimum is about 25%. A more preferred minimum is about 30%.The maximum ethylene content could be about 90% on a weight basis. Thepreferred maximum is about 85%, with the most preferred being about 80%.Preferably, the copolymers of this invention intended for use asviscosity modifier-dispersant contain from about 35 to 75 wt. %ethylene, and more preferably from about 50 to 70 wt. % ethylene.

The molecular weight of copolymer made in accordance with the presentinvention can vary over a wide range. It is believed that theweight-average molecular weight could be as low as about 2,000. Thepreferred minimum is about 10,000. The most preferred minimum is about20,000. It is believed that the maximum weight-average molecular weightcould be as high as about 12,000,000. The preferred maximum is about1,000,000. The most preferred maximum is about 750,000. An especiallypreferred range of weight-average molecular weight for copolymersintended for use as V.M. polymer is from 50,000 to 500,000.

The copolymers of this invention will also be generally characterized bya Mooney viscosity (i.e., ML(1,+4,) 125° C.) of from about 1 to 100,preferably from about 5 to 70, and more preferably from about 8 to 65,and by a thickening efficiency ("T.E.") of from about 0.4 to 5.0,preferably from about 1.0 to 4.2, most preferably from about 1.4 to 3.9.

Another feature of copolymer of the present invention is that themolecular weight distribution (MWD) is very narrow, as characterized byat least one of a ratio of M_(w) /M_(n) of less than 2 and a ratio ofM_(z) /M_(w) of less than 1.8. As relates to EPM and EPDM, a typicaladvantage of such copolymers having narrow MWD is resistance to sheardegradation. Particularly for oil additive applications, the preferredcopolymers have M_(w) /M_(n) less than about 1.5, with less than about1.25 being most preferred. The preferred M_(z) /M_(w) is less than about1.5, with less than about 1.2 being most preferred.

The copolymers of the instant invention may be produced bypolymerization of a reaction mixture comprised of catalyst, ethylene andat least one additional alpha-olefin monomer, wherein the amounts ofmonomer, and preferably ethylene, is varied during the course of thepolymerization in a controlled manner as will be hereinafter described.Solution polymerizations are preferred.

Any known solvent for the reaction mixture that is effective for thepurpose can be used in conducting solution polymerizations in accordancewith the present invention. For example, suitable solvents would behydrocarbon solvents such as aliphatic, cycloaliphatic and aromatichydrocarbon solvents, or halogenated versions of such solvents. Thepreferred solvents are C₁₂ or lower, straight chain or branched chain,saturated hydrocarbons, C₅ to C₉ saturated alicyclic or aromatichydrocarbons or C₂ to C₆ halogenated hydrocarbons. Most preferred areC₁₂ or lower, straight chain or branched chain hydrocarbons,particularly hexane. Non-limiting illustrative examples of solvents arebutane, pentane, hexane, heptane, cyclopentane, cyclohexane,cycloheptane, methyl cyclopentane, methyl cyclohexane, isooctane,benzene, toluene, xylene, chloroform, chlorobenzenes,tetrachloroethylene, dichloroethane and trichloroethane.

These polymerizations are carried out in a mix-free reactor system,which is one in which substantially no mixing occurs between portions ofthe reaction mixture that contain polymer chains initiated at differenttimes. Suitable reactors are a continuous flow tubular or a stirredbatch reactor. A tubular reactor is well known any is designed tominimize mixing of the reactants in the direction of flow. As a result,reactant concentration will vary along the reactor length. In contrast,the reaction mixture in a continuous flow stirred tank reactor (CFSTR)is blended with the incoming feed to produce a solution of essentiallyuniform composition everywhere in the reactor. Consequently, the growingchains in a portion of the reaction mixture will have a variety of agesand thus a single CFSTR is not suitable for the process of thisinvention. However, it is well known that 3 or more stirred tanks inseries with all of the catalyst fed to the first reactor can approximatethe performance of a tubular reactor. Accordingly, such tanks in seriesare considered to be in accordance with the present invention.

A batch reactor is a suitable vessel, preferably equipped with adequateagitation, to which the catalyst, solvent, and monomer are added at thestart of the polymerization. The charge of reactants is then left topolymerize for a time long enough to produce the desired product orchain segment. For economic reasons, a tubular reactor is preferred to abatch reactor for carrying out the processes of this invention.

In addition to the importance of the reactor system to make copolymersin accordance with the present invention, the polymerization should beconducted such that:

(a) the catalyst system produces essentially one active catalystspecies,

(b) the reaction mixture is essentially free of chain transfer agents,and

(c) the polymer chains are essentially all initiated simultaneously,which is at the same time for a batch reactor or at the same point alongthe length of the tube for a tubular reactor.

To prepare copolymer structures II and III above (and, optionally, toprepare copolymer structure I above), additional solvent and reactants(e.g., at least one of the ethylene, alpha-olefin and diene) will beadded either along the length of a tubular reactor or during the courseof polymerization in a batch reactor, or to selected stages of stirredreactors in series in a controlled manner (as will be hereinafterdescribed) to form the copolymers of this invention. However, it isnecessary to add essentially all of the catalyst at the inlet of thetube or at the onset of batch reactor operation to meet the requirementthat essentially all polymer chains are initiated simultaneously.

Accordingly, polymerization in accordance with the present invention arecarried out:

(a) in at least one mix-free reactor,

(b) using a catalyst system that produces essentially one activecatalyst species,

(c) using at least one reaction mixture which is essentially transferagent-free, and

(d) in such a manner and under conditions sufficient to initiatepropagation of essentially all polymer chains simultaneously.

Since the tubular reactor is the preferred reactor system for carryingout polymerizations in accordance with the present invention, thefollowing illustrative descriptions are drawn to that system, but willapply to other reactor systems as will readily occur to the artisanhaving the benefit of the present disclosure.

In practicing polymerization processes in accordance with the presentinvention, use is preferably made of at least one tubular reactor. Thus,in its simplest form, such a process would make use of but a single,reactor. However, as would readily occur to the artisan having thebenefit of the present disclosure, a series of reactors could be usedwith multiple monomer feed to vary intramolecular composition asdescribed below.

The composition of the catalyst used to produce alpha-olefin copolymershas a profound effect on copolymer product properties such ascompositional dispersity and MWD. The catalyst utilized in practicingprocesses in accordance with the present invention should be such as toyield essentially one active catalyst species in the reaction mixture.More specifically, it should yield one primary active catalyst specieswhich provides for substantially all of the polymerization reactionAdditional active catalyst species could provide as much as 35% (weight)of the total copolymer. Preferably, they should account for about 10% orless of the copolymer. Thus, the essentially one active species shouldprovide for at least 65% cf the total copolymer produced, preferably forat least 90% thereof. The extent to which a catalyst species contributesto the polymerization can be readily determined using thebelow-described techniques for characterizing catalyst according to thenumber of active catalyst species.

Techniques for characterizing catalyst according to the number of activecatalyst species are within the skill of the art, as evidenced by anarticle entitled "Ethylene-Propylene Copolymers. Reactivity Ratios,Evaluation and Significance", C. Cozewith and G. Ver Strate,Macromolecules, 4, 482 (1971), which is incorporated herein byreference.

It is disclosed by the authors that copolymers made in a continuous flowstirred reactor should have an MWD characterized by M_(w) /M_(n) =2 anda narrow Inter-CD when one active catalyst species is present. By acombination of fractionation and gel permeation chromatography (GPC) itis shown that for single active species catalysts the compositions ofthe fractions vary no more than +3% about the average and the MWD(weight- to number-average ratio) for these samples approaches 2. It isthis latter characteristic (M_(w) /M_(n) of about 2) that is deemed themore important in identifying a single active catalyst species. On theother hand, other catalysts gave copolymer with an Inter-CD greater than±10% about the average and multi-modal MWD often with M_(w) /M_(n)greater than 10. These other catalysts are deemed to have more than oneactive species.

Catalyst systems to be used in carrying out processes in accordance withthe present invention may be Ziegler catalysts, which may typicallyinclude:

(a) compound of a transition metal, i.e., a metal of Groups I-B, III-B,IVB, VB, VIB, VIIB and VIII of the Periodic Table, and (b) anorganometal compound of a metal of Groups I-A, II-A, II-B and III-A ofthe Periodic Table.

The preferred catalyst system in practicing processes in accordance withthe present invention comprises hydrocarbon-soluble vanadium compound inwhich the vanadium valence is 3 to 5 and an organo-aluminum compound,with the proviso that the catalyst yields essentially one activecatalyst species as described above. At least one of the vanadiumcompound/organo-aluminum pair selected must also contain avalence-bonded halogen.

In terms of formulas, vanadium compounds useful in practicing processesin accordance with the present invention could be: ##STR5##

where n=2-3, B Lewis base capable of making hydrocarbon-solublecomplexes with VCl₃, such as tetrahydrofuran, 2-methyl-tetrahydrofuranand dimethyl pyridine, and the dicarbonyl moiety is derived from adicarbonyl compound of the formula: ##STR6##

In formula (1) above, each R (which can be the same or different)preferably represents a C₁ to C₁₀ aliphatic, alicyclic or aromatichydrocarbon radical such as ethyl (Et), phenyl, isopropyl, butyl,propyl, n-butyl, i-butyl, t-butyl, hexyl, cyclohexyl, octyl, naphthyl,etc. R, preferably represents an alkylene divalent radical of 1 to 6carbons (e.g. --CH₂ --, --C₂ H₄ --, etc.). Nonlimiting illustrativeexamples of formula (1) compounds are vanadyl trihalides, alkoxy halidesand alkoxides such as VOCl₃, VOCl₂ (OBu) where Bu=butyl, and VO(OC₂H₅)₃. The most preferred vanadium compounds are VCl₄, VOCl₃, and VOCl₂(OR).

As already noted, the co-catalyst is preferably organo-aluminumcompound. In terms of chemical formulas, these compounds could be asfollows:

    ______________________________________                                        AlR.sub.3,          Al(OR)R.sub.2,                                            AlR.sub.2 Cl,       R.sub.2 Al--AlR.sub.2,                                    AlR,RCl,            AlR.sub.2 I,                                              Al.sub.2 R.sub.3 Cl.sub.3,                                                                        and                                                       AlRCl.sub.2,                                                                  ______________________________________                                    

where R and R, represent hydrocarbon radicals, the same or different, asdescribed above with respect to the vanadium compound formula. The mostpreferred organo-aluminum compound is an aluminum alkyl sesquichloridesuch as Al₂ Et₃ Cl₃ or Al₂ (iBu)₃ Cl₃.

In terms of performance, a catalyst system comprised of VCl₄ and Al₂ R₃Cl₃, preferably where R is ethyl, has been shown to be particularlyeffective. For best catalyst performance, the molar amounts of catalystcomponents added to the reaction mixture should provide a molar ratio ofaluminum/vanadium (Al/V) of at least about 2. The preferred minimum Al/Vis about 4. The maximum Al/V is based primarily on the considerations ofcatalyst expense and the desire to minimize the amount of chain transferthat may be caused by the organo-aluminum compound (as explained indetail below). Since, as is known certain organo-aluminum compounds actas chain transfer agents, if too much is present in the reaction mixturethe M_(w) /M_(n) of the copolymer may rise above 2. Based on theseconsiderations, the maximum Al/V could be about 25, however, a maximumof about 17 is more preferred. The most preferred maximum is about 15.

With reference again to processes for making copolymer in accordancewith the present invention, it is well known that certain combinationsof vanadium and aluminum compounds that can comprise the catalyst systemcan cause branching and gelation during the polymerization for polymerscontaining high levels of diene. To prevent this from happening Lewisbases such as ammonia, tetrahydrofuran, pyridine, tributylamine,tetrahydrothiophene, etc., can be added to the polymerization systemusing techniques well known to those skilled in the art.

Chain transfer agents for the Ziegler-catalyzed polymerization ofalpha-olefins are well known and are illustrated, by way of example, byhydrogen or diethyl zinc for the production of EPM and EPDM. Such agentsare very commonly used to control the molecular weight of EPM and EPDMproduced in continuous flow stirred reactors. For the essentially singleactive species Ziegler catalyst systems used in accordance with thepresent invention, addition of chain transfer agents to a CFSTR reducesthe polymer molecular weight but does not affect the molecular weightdistribution. On the other hand, chain transfer reactions during tubularreactor polymerization in accordance with the present invention broadenpolymer molecular weight distribution and Inter-CD. Thus the presence ofchain transfer agents in the reaction mixture should be minimized oromitted altogether. Although difficult to generalize for all possiblereactions, the amount of chain transfer agent used should be limited tothose amounts that provide copolymer product in accordance with thedesired limits as regards MWD and compositional dispersity. It isbelieved that the maximum amount of chain transfer agent present in thereaction mixture could be as high as about 0.2 mol/mol of transitionmetal, e.g., vanadium, again provided that the resulting copolymerproduct is in accordance with the desired limits as regards MWD andcompositional dispersity. Even in the absence of added chain transferagent, chain transfer reactions can occur because propylene and theorgano-aluminum cocatalyst can also act as chain transfer agents. Ingeneral, among the organo-aluminum compounds that in combination withthe vanadium compound yield just one active species, the organo-aluminumcompound that gives the highest copolymer molecular weight at acceptablecatalyst activity should be chosen. Furthermore, if the Al/V ratio hasan effect on the molecular weight of copolymer product, that Al/V shouldbe used which gives the highest molecular weight also at acceptablecatalyst activity. Chain transfer with propylene can best be limited byavoiding excessively elevated temperature during the polymerization asdescribed below.

Molecular weight distribution and Inter-CD are also broadened bycatalyst deactivation during the course of the polymerization whichleads to termination of growing chains. It is well known that thevanadium-based Ziegler catalysts used in accordance with the presentinvention are subject to such deactivation reactions which depend to anextent upon the composition of the catalyst Although the relationshipbetween active catalyst lifetime and catalyst system composition is notknown at present, for any given catalyst, deactivation can be reduced byusing the shortest residence time and lowest temperature in the reactorthat will produce the desired monomer conversions.

Polymerizations in accordance with the present invention should beconducted in such a manner and under conditions sufficient to initiatepropagation of essentially all copolymer chains simultaneously. This canbe accomplished by utilizing the process steps and conditions describedbelow.

The catalyst components are preferably premixed, that is, reacted toform active catalyst outside of the reactor, to ensure rapid chaininitiation. Aging of the premixed catalyst system, that is, the timespent by the catalyst components (e.g., vanadium compound andorgano-aluminum) in each other's presence outside of the reactor, shouldpreferably be kept within limits. If not aged for a sufficient period oftime, the components will not have reacted with each other sufficientlyto yield an adequate quantity of active catalyst species, with theresult of nonsimultaneous chain initiation. Also, it is known that theactivity of the catalyst species will decrease with time so that theaging must be kept below a maximum limit. It is believed that theminimum aging period, depending on such factors as concentration ofcatalyst components, temperature and mixing equipment, could be as lowas about 0.1 second. The preferred minimum aging period is about 0.5second, while the most preferred minimum aging period is about 1 second.While the maximum aging period could be higher, for the preferredvanadium/organo-aluminum catalyst system the preferred maximum is about200 seconds. A more preferred maximum is about 100 seconds. The mostpreferred maximum aging period is about 50 seconds. The premixing couldbe performed at low temperature such as 40° C. or below. It is preferredthat the premixing be performed at 25° C. or below, with 20° C. or belowbeing most preferred.

Preferably, the catalyst components are premixed in the presence of theselected polymerization diluent or solvent under rapid mixingconditions, e.g., at impingement Reynolds Numbers (NRE) of at least10,000, more preferably at least 50,000, and most preferably at least100,000. Impingement Reynolds number is defined as ##EQU5## where N isfluid flow velocity (cm./sec.), D is inside tube diameter (cm), ρ isfluid density (g./cm.³) and μ is fluid viscosity (poise).

The temperature of the reaction mixture should also be kept withincertain limits. The temperature at the reactor inlets should be highenough to provide complete, rapid chain initiation at the start of thepolymerization reaction. The length of time the reaction mixture spendsat high temperature must be short enough to minimize the amount ofundesirable chain transfer and catalyst deactivation reactions.

Temperature control of the reaction mixture is complicated somewhat bythe fact that the polymerization reaction generates large quantities ofheat. This problem is, preferably, taken care of by using prechilledfeed to the reactor to absorb the heat of polymerization. With thistechnique, the reactor is operated adiabatically and the temperature isallowed to increase during the course of polymerization. As analternative to feed prechill, heat can be removed from the reactionmixture, for example, by a heat exchanger surrounding at least a portionof the reactor or by well-known autorefrigeration techniques in the caseof batch reactors or multiple stirred reactors in series.

If adiabatic reactor operation is used, the inlet temperature of thereactor feed could be about from -50° C. to 150° C. It is believed thatthe outlet temperature of the reaction mixture could be as high as about200° C. The preferred maximum outlet temperature is about 70° C. Themost preferred maximum is about 60° C. In the absence of reactorcooling, such as by a cooling jacket, to remove the heat ofpolymerization, it has been determined (for a mid-range ethylene contentEP copolymer and a solvent with heat capacity similar to hexane) thatthe temperature of the reaction mixture will increase from reactor inletto outlet by about 13° C. per weight percent of copolymer in thereaction mixture (weight of copolymer per weight of solvent).

Having the benefit of the above disclosure, it would be well within theskill of the art to determine the operating temperature conditions formaking copolymer in accordance with the present invention. For example,assume an adiabatic reactor and an outlet temperature of 35° C. aredesired for a reaction mixture containing 5% copolymer. The reactionmixture will increase in temperature by about 13° C. for each weightpercent copolymer or 5 wt %×13° C./wt. %=65° C. To maintain an outlettemperature of 35° C., it will thus require a feed that has beenprechilled to 35°C-65° C.=-30° C. In the instance that external coolingis used to absorb the heat of polymerization, the feed inlet temperaturecould be higher with the other temperature constraints described aboveotherwise being applicable.

Because of heat removal and reactor temperature limitations, thepreferred maximum copolymer concentration at the reactor outlet is 25wt./100 wt. diluent. The most preferred maximum concentration is 15wt/100 wt. There is no lower limit to concentration due to reactoroperability, but for economic reasons it is preferred to have acopolymer concentration of at least 2 wt/100 wt. Most preferred is aconcentration of at least 3 wt/100 wt.

The rate of flow of the reaction mixture through the reactor should behigh enough to provide good mixing of the reactants in the radialdirection and minimize mixing in the axial direction. Good radial mixingis beneficial not only to both the Intra- and Inter-CD of the copolymerchains but also to minimize radial temperature gradients due to the heatgenerated by the polymerization reaction. Radial temperature gradientsin the case of multiple segment polymers will tend to broaden themolecular weight distribution of the copolymer since the polymerizationrate is faster in the high temperature regions resulting from poor heatdissipation. The artisan will recognize that achievement of theseobjectives is difficult in the case of highly viscous solutions. Thisproblem can be overcome to some extent through the use of radial mixingdevices such as static mixers (e.g., those produced by the KenicsCorporation).

It is believed that residence time of the reaction mixture in themix-free reactor can vary over a wide range. It is believed that theminimum could be as low as about 0.2 second. A preferred minimum isabout 0.5 second. The most preferred minimum is about 1 second. It isbelieved that the maximum could be as high as about 3600 seconds. Apreferred maximum is about 40 seconds. The most preferred maximum isabout 20 seconds.

Preferably, the fluid flow of the polymerization reaction mass throughthe tubular reactor will be under turbulent conditions, e.g., at a flowReynolds Number (NR) of at least 10,000, more preferably at least50,000, and most preferably at least 100,000 (e.g., 150,000 to 250,000),to provide the desired radial mixing of the fluid in the reactor. FlowReynolds Number is defined as ##EQU6## wherein N' is fluid flow velocity(cm./sec.), D, is inside tube diameter of the reactor (cm.), ρ is fluiddensity (g./cm.³) and μ is fluid viscosity (poise).

If desired, catalyst activators for the selected vanadium catalysts canbe used as long as they do not cause the criteria for a mix-free reactorto be violated, typically in amounts up to 20 mol %, generally up to 5mol %, based on the vanadium catalyst, e.g., butyl perchlorocrotonate,benzoyl chloride, and other activators disclosed in Ser. Nos. 504,945and 50,946, filed May 15, 1987, the disclosures of which are herebyincorporated by reference in their entirety Other useful catalystactivators include esters of halogenated organic acids, particularlyalkyl trichloroacetates, alkyl tribromoacetates, esters of ethyleneglycol monoalkyl (particularly monoethyl) ethers with trichloroaceticacid and alkyl perchlorocrotonates, and acyl halides. Specific examplesof these compounds include benzoyl chloride, methyl trichloroacetate,ethyl trichloroacetate, methyl tribromoacetate, ethyl tribromoacetate,ethylene glycol monoethyl ether trichloroacetate, ethylene glycolmonoethyl ether tribromoacetate, butyl perchlorocrotonate and methylperchlorocrotonate.

By practicing processes in accordance with the present invention,alpha-olefin copolymers having very narrow MWD can be made by directpolymerization. Although narrow MWD copolymers can be made using otherknown techniques, such as by fractionation or mechanical degradation,these techniques are considered to be impractical to the extent of beingunsuitable for commercial-scale operation. As regards EPM and EPDM madein accordance with the present invention, the products have good shearstability and (with specific intramolecular CD) excellent lowtemperature properties which make them especially suitable for lube oilapplications.

It is preferred that the Intra-CD of the copolymer is such that at leasttwo portions of an individual intramolecularly heterogeneous chain, eachportion comprising at least 5 weight percent of said chain, differ incomposition from one another by at least 5 weight percent ethylene TheIntra-CD can be such that at least two portions of copolymer chaindiffer by at least 10 weight percent ethylene. Differences of at least20 weight percent, as well as, 40 weight percent ethylene are alsoconsidered to be in accordance with the present invention.

It is also preferred that the Inter-CD of the copolymer is such that 95wt. % of the copolymer chains have an ethylene composition that differsfrom the copolymer average weight percent ethylene composition by 15 wt.% or less. The preferred Inter-CD is about 13% or less, with the mostpreferred being about 10% or less.

The particularly preferred copolymers of this invention are those thathave a weight average molecular weight of from about 20,000 to about250,000.

Grafting Materials

The materials or compounds that are grafted on the ethylene copolymerbackbone to form the grafted ethylene copolymers of the instantinvention are generally those materials that can be grafted onto saidethylene copolymers to form the grafted ethylene copolymers, whichgrafted copolymers are then reacted with the amido-amines or with thecarboxylic acid components and amido-amines to form the nitrogencontaining grafted ethylene copolymers of the instant invention. Thesematerials preferably contain olefinic unsaturation and furtherpreferably contain at least one of carboxylic acid moiety, ester moiety,or anhydride moiety. The olefinically unsaturated portion, i.e.,ethylenically unsaturated portion, is one which is capable of reachingwith the ethylene copolymer backbone, and upon reaction therewithbecomes saturated.

These materials are generally well known in the art as graftingmaterials and are generally commercially available or may be readilyprepared by well known conventional methods.

The preferred grafting materials are the carboxylic acid materials. Thecarboxylic acid material which is grafted to or reacted with theethylene copolymer to form the grafted ethylene copolymer is preferablyethylenically unsaturated, preferably monounsaturated, carboxylic acidmaterial and can be either a monocarboxylic or dicarboxylic acidmaterial. The dicarboxylic acid materials include (1) monounsaturated C₄to C₁₀ dicarboxylic acid wherein (a) the carboxyl groups are vicinyl,i.e., located on adjacent carbon atoms, and (b) at least one, preferablyboth, of said adjacent carbon atoms are part of said monounsaturation;and (2) derivatives of (1) such as anhydrides or C₁ to C₅ alcoholderived mono- or diesters of (1). Upon reaction with the ethylenecopolymer the monounsaturation of the dicarboxylic acid, anhydride, orester becomes saturated. Thus, for example, maleic anhydride becomes anethylene copolymer substituted succinic anhydride.

The monocarboxylic acid materials include (1) monounsaturated C₃ to C₁₀monocarboxylic acid wherein the carbon-carbon bond is conjugated to thecarboxy group, i.e., of the structure ##STR7## (2) derivatives of (1)such as C₁ to C₅ alcohol derived monoesters of (1). Upon reaction withthe ethylene copolymer, the monounsaturation of the monounsaturatedcarboxylic acid material becomes saturated. Thus, for example, acrylicacid becomes an ethylene copolymer substituted propionic acid, andmethacrylic acid becomes an ethylene copolymer substituted isobutyricacid.

Exemplary of such unsaturated mono- and dicarboxylic acids, oranhydrides and thereof include fumaric acid, itaconic acid, maleic acid,maleic anhydride, chloromaleic anhydride, acrylic acid, methacrylicacid, crotonic acid, cinnamic acid, methyl acrylate, ethyl acrylate,methyl methacrylate, etc.

Preferred carboxylic acid materials are the dicarboxylic acidanhydrides. Maleic anhydride or a derivative thereof is particularlypreferred as it does not appear to homopolymerize appreciably but graftsonto the ethylene copolymer to give two carboxylic acid functionalities.Such preferred materials have the generic formula ##STR8## wherein R'and R'' are independently hydrogen or a halogen.

Additionally, as taught by U.S. Pat. Nos. 4,160,739 and 4,161,452, bothof which are incorporated herein by reference, various unsaturatedcomonomers may be grafted on the ethylene copolymer together with theunsaturated carboxylic acid material Such graft monomer systems maycomprise one or a mixture of comonomers different from said unsaturatedcarboxylic acid material, and which contain only one copolymerizabledouble bond and are copolymerizable with said unsaturated acidcomponent.

Typically, such comonomers do not contain free carboxylic acid groupsand are esters containing alpha-ethylenic unsaturation in the acid oralcohol portion; hydrocarbons, both aliphatic and aromatic, containing,alpha-ethylenic unsaturation, such as the C₄ -C₁₂ alpha olefins, forexample hexene, nonene, dodecene, etc.; styrenes, for example styrene,alpha-methyl styrene, p-methyl styrene butyl styrene, etc.; and vinylmonomers, for example vinyl acetate, vinyl chloride, vinyl ketones suchas methyl and ethyl vinyl ketone, and nitrogen containing vinyl monomersuch as vinyl pyridine and vinyl pyrrolidine, etc. Comonomers containingfunctional groups which may cause crosslinking, gelation or otherinterfering reactions should be avoided, although minor amounts of suchcomonomers (up to about 10% by weight of the comonomer system) often canbe tolerated.

Specific useful copolymerizable comonomers include the following:

(A) Esters of saturated acids and unsaturated alcohols wherein thesaturated acids may be monobasic or polybasic acids containing up toabout 40 carbon atoms such as the following: acetic, propionic, butyric,valeric, caproic, stearic, oxalic, malonic, succinic, glutaric, adipic,pimelic, suberic, azelaic, sebacic, phthalic, isophthalic, terephthalic,hemimellitic, trimellitic, trimesic and the like, including mixtures.The unsaturated alcohols may be monohydroxy or polyhydroxy alcohols andmay contain up to about 40 carbon atoms, such as the following: allyl,methallyl, crotyl, 1-chloroallyl, 2-chloroallyl, cinnamyl, vinyl, methylvinyl, 1-phenallyl, butenyl, propargyl, 1-cyclohexene-3-ol, oleyl, andthe like, including mixtures.

(B) Esters of unsaturated monocarboxylic acids containing up to about 12carbon atoms such as acrylic, methacrylic and crotonic acid, and anesterifying agent containing up to about 50 carbon atoms, selected fromsaturated alcohols and alcohol epoxides. The saturated alcohols maypreferably contain up to about 40 carbon atoms and include monohydroxycompounds such as: methanol, ethanol, propanol, butanol, 2-ethylhexanol,octanol, dodecanol, cyclohexanol, cyclopentanol, neopentyl alcohol, andbenzyl alcohol; and alcohol ethers such as the monomethyl or monobutylethers of ethylene or propylene glycol, and the like, includingmixtures. The alcohol epoxides include fatty alcohol epoxides, glycidol,and various derivatives of alkylene oxides, epichlorohydrin, and thelike, including mixtures.

The components of the graft copolymerizable system are used in a ratioof unsaturated carboxylic acid material monomer component to comonomercomponent of about 1:4 to 4:1, preferably about 12 to 2:1 by weight.

Grafting of the Ethylene Copolymer

Grafting of the ethylene copolymer with the grafting material may beconducted by either conventional grafting processes or by a processwhich does not substantially adversely affect (substantially broaden)the narrow MWD of the ethylene copolymer, e.g., relatively lowtemperature and/or low shear process. While not wishing to be bound byany theory, it is believed that the reaction of the polyamine containingat least two reactive amino groups to form the nitrogen containinggrafted ethylene copolymer or with the polyol to form the estercontaining grafted ethylene copolymer produces a product having abroader molecular weight distribution than that of the ethylenecopolymer. Thus, even if the grafted ethylene copolymer is produced by aprocess which does not substantially broaden the MWD, the reaction ofthis narrow MWD grafted ethylene copolymer with the polyamine containingat least two reactive amino groups or with the polyol with result in aproduct having a broadened MWD.

In the grafting process which does not substantially adversely affect orbroaden the narrow MWD of the ethylene copolymer the graftingconditions, particularly temperature, are such that the narrow MWD asdefined herein of the ethylene copolymer reactant is not substantiallyadversely affected, i.e., is not substantially broadened. For thepurposes of this application the MWD is considered to be substantiallybroadened if the difference in MWD between the ungraftedethylene-alpha-olefin copolymer and the grafted ethylene-alpha-olefincopolymer is greater than about 10%. That is to say the graftingconditions are those which are effective to yield a graft copolymerwhich contains an ethylene copolymer backbone having substantially thesame of similar MWD distribution as the ethylene copolymer reactant. Bysubstantially the same or similar MWD is meant a MWD which is about 10%or less different from the MWD of the ungrafted ethylene-alpha-olefincopolymer, i.e., the difference between the MWD of ungraftedethylene-alpha-olefin copolymer and grafted ethylene-alpha-olefincopolymer is about I0% or less. If a high shear and/or high temperaturegrafting method such as extruder grafting is utilized the narrow MWD, asdefined hereinafore, of the ethylene copolymer is substantiallyadversely affected, i.e., is substantially broadened. That is to say theresultant grafted ethylene copolymer no longer has the narrow MWD of theungrafted ethylene copolymer.

Generally, the grafting conditions used to graft the grafting material,e.g., maleic anhydride, onto the ethylene-alpha-olefin copolymer depend,to a degree, upon the MWD of the ungrafted ethylene-alpha-olefincopolymer reactant. In general, the narrower the MWD of the ungraftedcopolymer reactant the milder the grafting conditions, i.e., temperatureand/or shear, that are utilized to produce a graftedethylene-alpha-olefin copolymer having a MWD which differs 10% or lessfrom the MWD of the ungrafted ethylene-alpha-olefin copolymer reactant.Thus, with ungrafted ethylene-alpha-olefin copolymers having a higher orbroader MWD, harsher grafting conditions, i.e., higher temperaturesand/or greater shear, can be used than with ungrafted copolymers havinga lower MWD to produce grafted ethylene-alpha-olefin copolymers having aMWD which differs, e.g., is higher, from the MWD of the ungraftedethylene-alpha-olefin copolymer reactant by no more than about 10%.Generally, grafting is carried out in solution, preferably using freeradical initiators, at temperatures below about 225° C., preferablybelow about 200° C., more preferably below about 190° C., and mostpreferably below about 180° C. in order to produce a grafted copolymerhaving this narrow MWD. Higher temperatures will result in a graftedpolymer which no longer has the substantially narrow MWD as describedherein.

The conventional grafting of the ethylene copolymer with the graftingmaterial such as carboxylic acid material may be by any suitable andwell-known conventional method such as thermally by the "ene" reaction,using copolymers containing unsaturation, such asethylene-propylene-diene polymers either chlorinated or unchlorinated,or more preferably it is by free-radical induced grafting; in solvent,preferably in a mineral lubricating oil as solvent.

The radical grafting is preferably carried out using free radicalinitiators such as peroxides, hydroperoxides, and azo compounds andpreferably those which have a boiling point greater than about 100° C.and which decompose thermally within the grafting temperature range toprovide said free radicals. The initiator is generally used at a levelof between about 0.005% and about 1%, based on the total weight of thepolymer solution, and temperatures of about 150° to 250° C., preferablyfrom about 150° C. to about 220° C. are used.

The ethylenically unsaturated carboxylic acid material, such as maleicanhydride, will be generally used in an amount ranging from about 0.01%to about 10%, preferably 0.1 to 2.0%, based on weight of the initialtotal solution. The aforesaid carboxylic acid material and free radicalinitiator are generally used in a weight percent ratio range of 1.0:1 to30:1, preferably 3.0:1 to 6:1.

In the practice of the instant invention when these ethylenicallyunsaturated grafting materials are grafted onto the aforedescribedethylene copolymer the resultant grafted copolymer contains the residueof the ethylene copolymer as the backbone and the residue of theethylenically unsaturated grafting material as the grafted moiety. Byresidues is meant the respective moieties produced by and remainingafter the grafting process or reaction. Thus, for example, while theethylenically unsaturated grafting material may be maleic anhydride,after the grafting reaction it is the succinic anhydride moiety that isgrafted or attached to the ethylene copolymer backbone. Thus, thissuccinic anhydride moiety is referred to herein as the residue of theethylenically unsaturated grafting material, i.e., residue of maleicanhydride.

A preferred method of grafting is by free-radical induced grafting insolvent, preferably in a mineral lubricating oil as solvent. Thefree-radical grafting is preferably carried out using free radicalinitiators such as peroxides, hydroperoxides, and azo compounds andpreferably those which have a boiling point greater than about 100° C.and which decompose thermally within the grafting temperature range toprovide said free radicals. Representative cf these free-radicalinitiators are asobutyro-nitrile, 2,5-di-methyl-hex-3-yne-2, 5bis-tertiary-butyl peroxide (sold as Lupersol 130) or its hexaneanalogue, di-tertiary butyl peroxide and dicumyl peroxide. The initiatoris generally used at a level of between about 0.005% and about 1%, basedon the total weight of the polymer solution, and temperatures of about150 to 220° C.

The initiator grafting is preferably carried out in an inert atmosphere,such as that obtained by nitrogen blanketing. While the grafting can becarried out in the presence of air, the yield of the desired graftpolymer is generally thereby decreased as compared to grafting under aninert atmosphere substantially free of oxygen. The grafting time willusually range from about 0.1 to 12 hours, preferably from about 0.5 to 6hours, more preferably 0.5 to 3 hours. The graft reaction will beusually carried out to at least approximately 4 times, preferably atleast about 6 times the half-life of the free-radical initiator at thereaction temperature employed, e.g. with 2,5-dimethyl hex-3-yne-2,5-bis(t-butyl peroxide) 2 hours at 160° C. and one hour at 170° C., etc.

In the grafting process, usually the copolymer solution is first heatedto grafting temperature and thereafter said grafting material such asunsaturated carboxylic acid material and initiator are added withagitation, although they could have been added prior to heating. Whenthe reaction is complete, the excess grafting material can be eliminatedby an inert gas purge, e.g. nitrogen sparging. Preferably the graftingmaterial such as carboxylic acid material that is added is kept belowits solubility limit in the polymer solution, e.g. below about 1 wt. %,preferably below 0.4 wt. % or less, of free maleic anhydride based onthe total weight of polymer-solvent solution, e.g. ethylene copolymermineral lubricating oil solution. Continuous or periodic addition of thegrafting material such as carboxylic acid material along with anappropriate portion of initiator, during the course of the reaction, canbe utilized to maintain the grafting material such as carboxylic acidmaterial below its solubility limits, while still obtaining the desireddegree of total grafting.

In the initiator grafting step the maleic anhydride or other carboxylicacid material used will be grafted onto both the polymer and the solventfor the reaction. Many solvents such as dichlorobenzene are relativelyinert and may be only slightly grafted, while mineral oil will tend tobe more grafted. The exact split of graft between the substrate presentdepends upon the polymer and its reactivity, the reactivity and type ofoil, the concentration of the polymer in the oil, and also upon themaintenance of the carboxylic acid material in solution during thecourse of the reaction and minimizing the presence of dispersed, butundissolved acid, e.g. the maleic anhydride. The undissolved acidmaterial appears to have an increased tendency to react to form oilinsoluble materials as opposed to dissolved acid material. The splitbetween grafted oil and grafted polymer may be measured empirically fromthe infrared analyses of the product dialyzed into oil and polymerfractions.

The grafting is preferably carried out in a mineral lubricating oilwhich need not be removed after the grafting step but can be used as thesolvent in the subsequent reaction of the graft polymer with thepolyamine or polyol and as a solvent for the end product to form thelubricating additive concentrate.

The solution grafting step when carried out in the presence of a hightemperature decomposable peroxide can be accomplished withoutsubstantial degradation of the chain length (molecular weight) of theethylene containing polymer. This can be an advantage as opposed to hightemperature thermal reactions which depend on degradation to apparentlyform free radical reactive sites. Measurement of molecular weights anddegradation can be evaluated by determination of the thickeningefficiency (T.E.) of the polymer as will later be described.

The amount of grafting material such as carboxylic acid material used inthe grafting reaction is an amount which is effective to provide agrafted ethylene copolymer which upon further reaction with theamido-amine as described hereinafter provides a material exhibiting theproperties of a multifunctional viscosity index improver additive, morespecifically a viscosity index improver-dispersant additive, i.e., amaterial having both V.I. improving and dispersancy properties in anoleaginous composition. That is to say, an amount which is effective toprovide, upon reaction of the grafted ethylene copolymer with theamido-amine, an oleaginous composition exhibiting improved viscometricand dispersancy properties. Generally, this amount of grafting material,e.g., moles of carboxylic acid material such as maleic anhydride, is anamount which is effective to provide a grafted ethylene copolymer, e.g.,ethylene-alpha-olefin substituted carboxylic acid material such asethylene- propylene substituted succinic anhydride, containing anaverage number of acid material moieties, e.g., succinic anhydride,grafted to or present on a 10,000 number average molecular weightsegment of a mole of ethylene copolymer of at least about 0.1,preferably at least about 0.5, and more preferably at least about 1. Themaximum average number of grafted moieties present per 10,000 averagenumber molecular weight segment of a mole of ethylene copolymer backboneshould not exceed about 10, preferably about 7 and more preferably about5. Preferably, the average number, moles, of grafted moieties presentper mole of ethylene copolymer backbone is at least about 0.6,preferably at least about 0.8, and more preferably at least about 1.Preferably, the maximum average number of grafted moieties grafted to orpresent per mole of ethylene copolymer backbone should generally notexceed about 10, preferably about 7, and more preferably about 5. Thus,for example, a mole of grafted ethylene copolymer, e.g.,ethylenepropylene substituted succinic anhydride, containing an ethylenecopolymer backbone such as an ethylene- propylene backbone having anaverage number molecular weight of 50,000 contains grafted to saidbackbone an average number of succinic anhydride moieties of from about0.5 to about 50, preferably from about 0.6 to about 10. Typically, fromabout 0.2 to about 12, preferably from about 0 4 to about 6 moles ofsaid carboxylic acid material are charged to the reactor per mole ofethylene copolymer charged.

Normally, not all of the ethylene copolymer reacts with the carboxylicacid material, e.g., maleic anhydride, to produce a grafted ethylenecopolymer, e.g., ethylene-propylene substituted succinic anhydride. Theresultant reaction product mixture, therefore, contains reacted orgrafted ethylene copolymer, e.g., ethylene-propylene substitutedsuccinic anhydride, unreacted or ungrafted ethylene copolymer, andunreacted grafting material, e.g., maleic anhydride. The unreactedethylene copolymer is typically not removed from the reaction productmixture, and the reaction product mixture, generally stripped of anyunreacted grafting material, is utilized as is or is employed forfurther reaction with the amine as described hereinafter.

Characterization of the average number of moles of grafting materialsuch as carboxylic acid material, e.g., maleic anhydride, which havereacted per mole of ethylene copolymer charged to the reaction (whetherit has undergone reaction or not) is defined herein as the averagenumber of grafted moieties grafted to or present per mole of ethylenecopolymer the resulting reaction product mixture can be subsequentlymodified, i.e., increased or decreased by techniques known in the art,such modifications do not alter the average number of grafted moietiesas defined above. The term grafted ethylene copolymer is intended torefer to the reaction product mixture whether it has undergone suchmodification or not.

The grafted, preferably acid material grafted, ethylene copolymer isreacted with a polyamine or polyol to form the nitrogen or estercontaining grafted ethylene copolymers of the instant invention. Whenthe grafted ethylene copolymer is reacted with a polyamine the resultantproduct is a nitrogen containing grafted ethylene copolymer.

The Amido-Amine

As described above, the amido-amine comprises a reaction product of atleast one amine and an alpha, betaethylenically unsaturated compound offormula ##STR9## wherein X is sulfur or oxygen, Y is --OR⁴, --SR⁴, or--NR⁴ (R⁵), and R¹, R², R³, R⁴ and R5 are the same or different and arehydrogen or substituted or unsubstituted hydrocarbyl.

The polyamines useful in this invention comprise polyamines, mostpreferably polyalkylene polyamines, of about 2 to 60, preferably 2 to 40(e.g. 3 to 20), total carbon atoms and about 1 to 12, preferably 2 to12, more preferably 3 to 12, and most preferably at least 5 (e.g., 5 to9) nitrogen atoms in the molecule. These amines may be hydrocarbylamines or may be hydrocarbyl amines including other groups, e.g, hydroxygroups, alkoxy groups, amide groups, nitriles, imidazoline groups, andthe like. Hydroxy amines with 1 to 6 hydroxy groups, preferably 1 to 3hydroxy groups are particularly useful. Preferred amines are aliphaticsaturated amines, including those of the general formulas: ##STR10##wherein R, R', R'' and R''' are independently selected from the groupconsisting of hydrogen; C₁ to C₂₅ straight or branched chain alkylradicals; C₁ to C₁₂ alkoxy C₂ to C₆ alkylene radicals; C₂ to C₁₂ hydroxyamino alkylene radicals; and C₁ to C₁₂ alkylamino C₂ to C₆ alkyleneradicals; and wherein R"' can additionally comprise a moiety of theformula: ##STR11## wherein R' is as defined above, and wherein s and s'can be the same or a different number of from 2 to 6, preferably 2 to 4;and t and t' can be the same or different and are numbers of from 0 to10, preferably 2 to 7, and most preferably about 3 to 7, with theproviso that the sum of t and t' is not greater than 15. To assure afacile reaction, it is preferred that R, R', R'', R''', s, s', t and t'be selected in a manner sufficient to provide the compounds of FormulasII and III with typically at least one primary or secondary amine group,preferably at least two primary or secondary amine groups. This can beachieved by selecting at least one of said R, R', R'' or R''' groups tobe hydrogen or by letting t in Formula III be at least one when R"' is Hor when the IV moiety possesses a secondary amino group. The mostpreferred amine of the above formulas are represented by Formula III andcontain at least two primary amine groups and at least one, andpreferably at least three, secondary amine groups.

Non-limiting examples of suitable amine compounds include:1,2-diaminoethane; 1,3-diaminopropane; 1,4-diaminobutane;1,6-diaminohexane; polyethylene amines such as diethylene triamine;triethylene tetramine; tetraethylene pentamine; polypropylene aminessuch as 1,2-propylene diamine; di-(1,2-propylene)triamine;di-(1,3-propylene) triamine; N,N-dimethyl-1,3-di aminopropane;N,N-di-(2-aminoethyl) ethylene diamine;N,N-di(2-hydroxyethyl)-1,3-propylene diamine; 3-dodecyloxypropyIamine;N-dodecyl-1,3-propane diamine; tris hydroxymethylaminomethane (THAM);diisopropanol amine; diethanol amine; triethanol amine; mono-, di-, andtri-tallow amines; amino morpholines such asN-(3-aminopropyl)morpholine; and mixtures thereof.

Other useful amine compounds include: alicyclic diamines such as1,4-di(aminomethyl) cyclohexane, and heterocyclic nitrogen compoundssuch as imidazolines, and N-aminoalkyl piperazines of the generalformula (V): ##STR12## wherein p₁ and p₂ are the same or different andare each integers of from 1 to 4, and n₁, n₂ and n₃ are the same ordifferent and are each integers of from 1 to 3. Non-limiting examples ofsuch amines include 2-pentadecyl imidazoline: N-(2-aminoethyl)piperazine; etc.

Commercial mixtures of amine compounds may advantageously be used. Forexample, one process for preparing alkylere amines involves the reactionof an involves the reaction of an alkylene dihalide (such as ethylenedichloride or propylene dichloride) with ammonia, which results in acomplex mixture of alkylene amines wherein pairs of nitrogens are joinedby alkylene groups, forming such compounds as diethylene triamine,triethylenetetramine, tetraethylene pentamine and isomeric piperazines.Low cost poly(ethyleneamines) compounds averaging about 5 to 7 nitrogenatoms per molecule are available commercially under trade names such as"Polyamine H", "Polyamine 400", "Dow Polyamine E-100", etc.

Useful amines also include polyoxyalkylene polyamines such as those ofthe formulae:

    NH.sub.2 --alkylene--O-alkylene).sub.m NH.sub.2            (VI)

where m has a value of about 3 to 70 and preferably 10 to 35; and

    R--alkylene--O-alkylene).sub.n NH.sub.2 ).sub.a            (VII)

where "n" has a value of about 1 to 40 with the provision that the sumof all the n's is from about 3 to about 70 and preferably from about 6to about 35, and R is a polyvalent saturated hydrocarbon radical of upto ten carbon atoms wherein the number of substituents on the R group isrepresented by the value of "a", which is a number of from 3 to 6. Thealkylene groups in either formula (VI) or (VII) may be straight orbranched chains containing about 2 to 7, and preferably about 2 to 4carbon atoms.

The polyoxyalkylene polyamines of formulas (VI) or (VII) above,preferably polyoxyalkylene diamines and polyoxyalkylene triamines, mayhave average molecular weights ranging from about 200 to about 4000 andpreferably from about 400 to about 2000. The preferred polyoxyalkylenepolyoxyalkylene polyamines include the polyoxyethylene andpolyoxypropylene diamines and the polyoxypropylene triamines havingaverage molecular weights ranging from about 200 to 2000. Thepolyoxyalkylene polyamines are commercially available and may beobtained, for example, from the Jefferson Chemical Company, Inc. underthe trade name "Jeffamines D-230, D-400, D-1000, D-2000, T-403", etc.

Additional amines useful in the present invention are described in U.S.Pat. No. 3,445,441, the disclosure of which is hereby incorporated byreference in its entirety.

Thus, any polyamine, whether aliphatic, cycloaliphatic, aromatic,heterocyclic, etc., can be employed provided it is capable of addingacross the acrylic double bond and amidifying with for example thecarbonyl group (--C(O)--) of the acrylate-type compound of formula I, orwith the thiocarbonyl group (--C(S)--) of the thioacrylate-type compoundof formula I.

The alpha, beta ethylenically unsaturated compounds employed in thisinvention comprise at least one member selected from the groupconsisting of alpha, beta ethylenically unsaturated compounds of theformula: ##STR13## wherein X is sulfur or oxygen, Y is --OR⁴, --SR⁴, or--NR⁴ (R⁵), and R.sup., R², R³, R⁴ and R⁵ are the same or different andare hydrogen or substituted or unsubstituted hydrocarbyl.

When R¹, R², R³, R⁴ or R⁵ are hydrocarbyl, these groups can comprisealkyl, cycloalkyl, aryl, alkaryl, aralkyl or heterocyclic, which can besubstituted with groups which are substantially inert to any componentof the reaction mixture under conditions selected for preparation of theamido-amine. Such substituent groups include hydroxy, halide (e.g., Cl,Fl, I, Br), --SH and alkylthio. When one or more of R¹ through R⁵ arealkyl, such alkyl groups can be straight or branched chain, and willgenerally contain from 1 to 20, more usually from 1 to 10, andpreferably from 1 to 4, carbon atoms. Illustrative of such alkyl groupsare methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl,decyl, dodecyl, tridecyl, hexadecyl, octadecyl and the like. When one ormore of R¹ through R⁵ are aryl, the aryl group will generally containfrom 6 to 10 carbon atoms (e.g., phenyl, naphthyl).

When one or more of R¹ through R⁵ are alkaryl, the alkaryl group willgenerally contain from about 7 to 20 carbon atoms, and preferably from 7to 12 carbon atoms. Illustrative of such alkaryl groups are tolyl,m-ethylphenyl, o-ethyltolyl, and m-hexyltolyl. When one or more of R¹through R⁵ are aralkyl, the aryl component generally consists of phenylor (C₁ to C₆) alkyl-substituted phenol and the alkyl component generallycontains from 1 to 12 carbon atoms, and preferably from 1 to 6 carbonatoms. Examples of such aralkyl groups are benzyl, o-ethylbenzyl, and4-isobutylbenzyl. When one or more of R¹ and R⁵ are cycloalkyl, thecycloalkyl group will generally contain from 3 to 12 carbon atoms, andpreferably from 3 to 6 carbon atoms. Illustrative of such cycloalkylgroups are cyclopropyl, cyclobutyl, cyclohexyl, cyclooctyl, andcyclododecyl. When one or more of R¹ through R⁵ are heterocyclic, theheterocyclic group generally consists of a compound having at least onering of 6 to 12 members in which on or more ring carbon atoms isreplaced by oxygen or nitrogen. Examples of such heterocyclic groups arefuryl, pyranyl, pyridyl, piperidyl, dioxanyl, tetrahydrofuryl, pyrazinyland 1,4-oxazinyl.

The alpha, beta ethylenically unsaturated carboxylate compounds employedherein have the following formula: ##STR14## wherein R¹, R², R³, and R⁴are the same or different and are hydrogen or substituted orunsubstituted hydrocarbyl as defined above. Examples of such alpha,beta-ethylenically unsaturated carboxylate compounds of formula VIII areacrylic acid, methacrylic acid, the methyl, ethyl, isopropyl, n-butyl,and isobutyl esters of acrylic and methacrylic acids, 2-butenoic acid,2-hexenoic acid, 2-decenoic acid, 3-methyl-2-heptenoic acid,3-methyl-2-butenoic acid, 3-phenyl-2-propenoic acid,3-cyclohexyl-2-butenoic acid, 2-methyl-2-butenoic acid,2-propyl-2-propenoic acid, 2-isopropyl-2-hexenoic acid,2,3-dimethyl-2-butenoic acid, 3-cyclohexyl-2-methyl-2-pentenoic acid,2-propenoic acid, methyl 2-propenoate, methyl 2-methyl 2-propenoate,methyl 2-butenoate, ethyl 2-hexenoate, isopropyl 2-decenoate, phenyl2-pentenoate, tertiary butyl 2-propenoate, octadecyl 2-propenoate,dodecyl 2-decenoate, cyclopropyl 2,3-dimethyl-2-butenoate, methyl3-phenyl-2-propenoate, and the like.

The alpha, beta ethylenically unsaturated carboxylate thioestercompounds employed herein have the following formula: ##STR15## whereinR¹, R², R³, and R⁴ are the same or different and are hydrogen orsubstituted or unsubstituted hydrocarbyl as defined above. Examples ofsuch alpha, beta-ethylenically unsaturated carboxylate thioesters offormula IX are methylmercapto 2-butenoate, ethylmercapto 2-hexenoate,isopropylmercapto 2-decenoate, phenylmercapto 2-pentenoate, tertiarybutylmercapto 2-propenoate, octadecylmercapto 2-propenoate,dodecylmercapto 2-decenoate, cyclopropylmercapto2,3-dimethyl-2-butenoate, methylmercapto 3-phenyl-2-propenoate,methylmercapto 2-propenoate, methylmercapto 2-methyl-2-propenoate, andthe like.

The alpha, beta ethylenically unsaturated carboxyamide compoundsemployed herein have the following formula: ##STR16## wherein R¹, R²,R³, R⁴ and R⁵ are the same or different and are hydrogen or substitutedor unsubstituted hydrocarbyl as defined above. Examples of alpha,beta-ethylenically unsaturated carboxyamides of formula X are2-butenamide, 2-hexenamide, 2-decenamide, 3-methyl-2-heptenamide,3-methyl-2-butenamide, 3-phenyl-2-propenamide,3-cyclohexyl-2-butenamide, 2-methyl-2-butenamide,2-propyl-2-propenamide, 2-isopropyl-2-hexenamide,2,3-dimethyl-2-butenamide, 3-cyclohexyl-2-methyl-2-pentenamide, N-methyl2-butenamide, N,N-diethyl 2-hexenamide, N-isopropyl 2-decenamide,N-phenyl 2-pentenamide, N-tertiary butyl 2-propenamide, N-octadecyl2-propenamide, N-N-didodecyl 2-decenamide, N-cyclopropyl2,3-dimethyl-2-butenamide, N-methyl 3-phenyl-2-propenamide,2-propenamide, 2-methyl-2-propenamide, 2-ethyl-2-propenamide and thelike.

The alpha, beta ethylenically unsaturated thiocarboxylate compoundsemployed herein have the following formula: ##STR17## wherein R¹, R²,R³, and R⁴ are the same or different and are hydrogen or substituted orunsubstituted hydrocarbyl as defined above. Examples of alpha,beta-ethylenically unsaturated thiocarboxylate compounds of formula XIare 2-butenthioic acid, 2-hexenthioic acid, 2-decenthioic acid,3-methyl-2-heptenthioic acid, 3-methyl-2-butenthioic acid,3-phenyl-2-propenthioic acid, 3-cyclohexyl-2-butenthioic acid,2-methyl-2-butenthioic acid, 2-propyl-2-propenthioic acid,2-isopropyl-2-hexenthioic acid, 2,3-dimethyl-2-butenthioic acid,3-cyclohexyl-2-methyl-2-pententhioic acid, 2-propenthioic acid, methyl2-propenthioate, methyl 2-methyl 2-propenthioate, methyl 2-butenthioate,ethyl 2-hexenthioate, isopropyl 2-decenthioate, phenyl 2-pententhioate,tertiary butyl 2-propenthioate, octadecyl 2-propenthioate, dodecyl2-decenthioate, cyclopropyl 2,3-dimethyl-2-butenthioate, methyl3-phenyl-2-propenthioate, and the like.

The alpha, beta ethylenically unsaturated dithioic acid and acid estercompounds employed herein have the following formula: ##STR18## whereinR¹, R², R³, and R⁴ are the same or different and are hydrogen orsubstituted or unsubstituted hydrocarbyl as defined above. Examples ofalpha, beta-ethylenically unsaturated dithioic acids and acid esters offormula XII are 2-butendithioic acid, 2-hexendithioic acid,2-decendithioic acid, 3-methyl-2-heptendithioic acid,3-methyl-2-butendithioic acid, 3-phenyl-2-propendithioic acid,3-cyclohexyl-2-butendithioic acid, 2-methyl-2-butendithioic acid,2-propyl-2-propendithioic acid, 2-isopropyl-2-hexendithioic acid,2,3-dimethyl-2-butendithioic acid,3-cyclohexyl-2-methyl-2-pentendithioic acid, 2-propendithioic acid,methyl 2-propendithioate, methyl 2-methyl 2-proendithioate, methyl2-butendithioate, ethyl 2-hexendithioate, isopropyl 2-decendithioate,phenyl 2-pentendithioate, tertiary butyl 2-propendithioate,3-methyl-2-butenthioic acid, 3-phenyl-2-propenthioic acid,3-cyclohexyl-2-butenthioic acid, 2-methyl-2-butenthioic acid,2-propyl-2-propenthioic acid, 2-isopropyl-2-hex enthioic acid,2,3-dimethyl-2-butenthioic acid, 3-cyclohexyl-2-methyl-2-pententhioicacid, 2-propenthioic acid, methyl 2-propenthioate, methyl 2-methyl2-propenthioate, methyl 2-butenthioate, ethyl 2-hexenthioate, isopropyl2-decenthioate, phenyl 2-pententhioate, tertiary butyl 2-propenthioate,octadecyl 2-propenthioate, dodecyl 2-propenthioate, octadecyl2-propenthioate, dodecyl 2-decenthioate, cyclopropyl2,3-dimethyl-2-butenthioate, methyl 3-phenyl-2.propenthioate, and thelike.

The alpha, beta ethylenically unsaturated dithioic acid and acid estercompounds employed herein have the following formula: ##STR19## whereinR¹, R², R³, and R⁴ are the same or different and are hydrogen orsubstituted or unsubstituted hydrocarbyl as defined above. Examples ofalpha, beta-ethylenically, unsaturated dithioic acids and acid esters offormula XII are 2-butendithioic acid, 2-hexendithioic acid,2-decendithioic acid, 3-methyl-2-heptendithioic acid,3-methyl-2-butendithioic acid, 3-phenyl-2-propendithioic acid,3-cyclohexyl-2-butendithioic acid, 2-methyl-2-butendithioic acid,2-propyl-2-propendithioic acid, 2-isopropyl-2-hexendithioic acid,2,3-dimethyl-2-butendithioic acid,3-cyclohexyl-2-methyl-2-pentendithioic acid, 2-propendithioic acid,methyl 2-propendithioate, methyl 2-methyl 2-proendithioate, methyl2-butendithioate, ethyl 2-hexendithioate, isopropyl 2-decendithioate,phenyl 2-pentendithioate, tertiary butyl 2-propendithioate, octadecyl2-propendithioate, dodecyl 2-decendithioate, cyclopropyl2,3-dimethyl-2-butendithioate, methyl 3-phenyl-2-propendithioate, andthe like.

The alpha, beta ethylenically unsaturated thiocarboxyamide compoundsemployed herein have the following formula: ##STR20## wherein R¹, R²,R³, R⁴ and R⁵ are the same or different and are hydrogen or substitutedor unsubstituted hydrocarbyl as defined above. Examples of alpha,beta-ethylenically unsaturated thiocarboxyamides of formula XIII are2-butenthioamide, 2-hexenthioamide, 2-decenthicamide,3-methyl-2-heptenthioamide, 3-methyl-2-butenthioamide,3-phenyl-2-propenthioamide, 3-cyclohexyl-2-butenthioamide,2-methyl-2-butenthioamide, 2-propyl-2-propenthioamide,2-isopropyl-2-hexenthioamide, 2,3-dimethyl-2-butenthioamide,3-cyclohexyl-2-methyl-2-pententhioamide, N-methyl 2-butenthioamide,N,N-diethyl 2-hexenthioamide, N-isopropyl 2-decenthioamide, N-phenyl2-pententhioamide, N-tertiary butyl 2-propenthioamide, N-octadecyl2-propenthioamide, N-N-didodecyl 2-decenthioamide, N-cyclopropyl2,3-dimethyl-2-butenthioamide, N-methyl 3-phenyl-2-propenthioamide,2-propenthioamide, 2-methyl-2-propenthioamide, 2-ethyl-2-propenthioamideand the like.

Preferred compounds for reaction with the polyamines in accordance withthis invention are lower alkyl esters of acrylic and (lower alkyl)substituted acrylic acid. Illustrative of such preferred compounds arecompounds of the formula: ##STR21## where R³ is hydrogen or a C₁ to C₄alkyl group, such as methyl, and R⁴ is hydrogen or a C₁ to C₄ alkylgroup, capable of being removed so as to form an amido group, forexample, methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl,aryl, hexyl, etc. In the preferred embodiments these compounds areacrylic and methacrylic esters such as methyl, ethyl or propyl acrylate,methyl, ethyl or propyl methacrylate. When the selected alpha,beta-unsaturated compound comprises a compound of formula I wherein X isoxygen, the resulting reaction product with the polyamine contains atleast one amide linkage (-C(O)N<)and such materials are herein termed"amido-amines." Similarly, when the selected alpha, beta unsaturatedcompound of formula I comprises a compound wherein X is sulfur, theresulting reaction product with the polyamine contains thioamide linkage(-C(S)N<) and these material are herein termed "thioamido-amines." Forconvenience, the following discussion is directed to the preparation anduse of amido-amines, although it will be understood that such discussionis also applicable to the thioamide-amines.

The type of amido-amine formed varies with reaction conditions. Forexample, a more linear amido-amine is formed where substantiallyequimolar amounts of the unsaturated carboxylate and polyamine arereacted. The presence of excesses of the ethylenically unsaturatedreactant of formula I tends to yield an amido-amine which is morecross-linked than that obtained where substantially equimolar amounts ofreactants are employed. Where for economic or other reasons across-linked amido-amine using excess amine is desired, generally amolar excess of the ethylenically unsaturated reactant of about at least10%, such as 10-300%, or greater, for example 25-200%, is employed. Formore efficient cross-linking an excess of carboxylated material shouldpreferably be used since a cleaner reaction ensues. For example, a molarexcess of about 10-100% or greater such as 10-50%, but preferably anexcess of 30-50%, of the carboxylated material. Larger excess can beemployed if desired.

In summary, without considering other factors, equimolar amounts ofreactants tend to produce a more linear amido-amine whereas excess ofthe formula I reactant tends to yield a more cross-linked amido-amine.It should be noted that the higher the polyamine (i.e., in greater thenumber of amino groups on the molecule) the greater the statisticalprobability of cross-linking since, for example, atetraalkylenepentamine, such as tetraethylene pentamine ##STR22## hasmore labile hydrogens that ethylene diamine.

These amido-amine adducts so formed are characterized by both amido andamino groups. In their simplest embodiments they may be represented byunits of the following idealized formula: ##STR23## wherein the R's,which may be the same or different, are hydrogen or a substituted group,such as a hydrocarbon group, for example, alkyl, alkenyl, alkynyl, aryl,etc., and A is a moiety of the polyamine which, for example, may bearyl, cycloalkyl, alkyl, etc., and n is an integer such as 1-10 orgreater. The amido-amine adducts preferably contain an average of form 1to 3 amido groups per molecule of the amido-amine adduct.

The above simplified formula represents a linear amido-amine polymer.However, cross-linked polymers may also be formed by employing certainconditions since the polymer has labile hydrogens which can furtherreact with either the unsaturated moiety by adding across the doublebond or by amidifying with a carboxylate group.

Preferably, however, the amido-amines of this invention are notcross-linked to any substantial degree, and more preferably aresubstantially linear.

Preferably, the polyamine reactant contains at least one primary amine(and more preferably from 2 to 4 primary amines) group per molecule, andthe polyamine and the unsaturated reactant of formula I are contacted inan amount of from about 1 to 10, more preferably from about 2 to 6, andmost preferably from about 3 to 5, equivalents of primary amine in thepolyamine reactant per mole of the unsaturated reactant of formula I.

The reaction between the selected polyamine and acrylate-type compoundis carried out at any suitable temperature. Temperatures up to thedecomposition points of reactants and products can be employed Inpractice, one generally carries out the reaction by heating thereactants below 100° C., such as 80°-90° C., for a suitable period oftime, such as a few hours. Where an acrylic-type ester is employed, theprogress of the reaction can be judged by the removal of the alcohol informing the amide. During the early part of the reaction alcohol isremoved quite readily below 100° C. in the case of low boiling alcoholssuch as methanol or ethanol. As the reaction slows, the temperature israised to push the polymerization to completion and the temperature maybe raised to 150° C. toward the end of the reaction. Removal of alcoholis a convenient method of judging the progress and completion of thereaction which is generally continued until no more alcohol is evolved.Based on removal of alcohol, the yields are generally stoichiometric. Inmore difficult reactions, yield of at least 95 % are generally obtained.

Similarly, it will be understood that the reaction of an ethylenicallyunsaturated carboxylate thioester of formula IX liberates thecorresponding HSR⁴ compound (e.g., H₂ S when R⁴ is hydrogen) as aby-product, and the reaction of an ethylenically unsaturatedcarboxyamide of formula X liberates the corresponding HNR⁴ (R⁵) compound(e.g., ammonia when R⁴ and R⁵ are each hydrogen) as by-product.

The reaction time involved can vary widely depending on a wide varietyof factors. For example, there is a relationship between time andtemperature. In general, lower temperature demands longer times.Usually, reaction times of from about 2 to 30 hours, such as 5 to 25hours, and preferably 3 to 10 hours will be employed.

Although one can employ a solvent, the reaction can be run without theuse of any solvent. In fact, where a high degree of cross-linking isdesired, it is preferably to avoid the use of a solvent and mostparticularly to avoid a polar solvent such as water. However, takinginto consideration the effect of solvent on the reaction, where desired,any suitable solvent can be employed, whether organic or inorganic,polar or non-polar.

As an example of the amido-amine adducts, the reaction of tetraethylenepentaamine (TEPA) with methyl acrylate can be illustrated as follows:##STR24##

REACTION OF GRAFTED ETHYLENE COPOLYMER WITH AMIDO AMINE

The grafted high molecular weight ethylene copolymer, preferably insolution, such as an oil solution, containing 5 to 95 wt. %, preferably5 to 30 wt. %, and more preferably 10 to 20 wt. % of said graftedethylene copolymer, is readily reacted with the amido-amine byintroducing the amido amine into said grafted ethylene copolymercontaining solution and heating at a temperature of from about 100° C.to 250° C., preferably from 125° to 175° C., for from about 1 to 10hours, usually about 2 to about 6 hours. The heating is preferablycarried out, in the case of ethylene copolymer substituted dicarboxylicacid material, to favor formation of imides or mixtures of imides andamides rather than amides and salts. In the case of ethylene copolymersubstituted monocarboxylic acid material heating is preferably carriedout to favor formation of amides rather than salts. Removal of waterassures completion of the imidation/ amidation reaction. Reaction ratioscan vary considerably, depending upon the reactants, amounts of excess,type of bonds formed, etc. Generally, from about 1 to 5, preferably fromabout 1.5 to 3 moles of ethylene copolymer substituted monocarboxylic ordicarboxylic acid moiety content, e.g., grafted succinic anhydridecontent, is used per equivalent of amido amine reactant, e.g., amine.

An example of the reaction of an amido amine reactant with ethylenecopolymer substituted dicarboxylic acid material is the reaction ofethylene-propylene copolymer substituted succinic anhydride (EPSA) witha poly amido-amine having two terminal --NH₂ groups, which can beillustrated as follows: ##STR25## wherein x and y are each integers offrom 0 to 10, with the proviso that the sum of x+y is at least 1, e.g.,1 to 20.

An example of the reaction of an amido-amine reactant with an ethylenecopolymer substituted monocarboxylic acid material is the reaction ofethylene-propylene copolymer substituted propionic acid (EPA) with apoly amido-amine having two terminal --NH₂ groups, which can beillustrated as follows: ##STR26## wherein x and y are each integers offrom 0 to 10, with the proviso that the sum of x+y is at least 1, e.g.,1 to 20 and wherein Z¹ and Z² are the same or different and are eachmoieties of the formula: ##STR27##

It will be understood that the amido-amine reactant can be employedalone or in admixture with any of the above described amines, such asthe polyalkylene polyamines, useful in preparing the amido-aminereactant.

Preferably, the ethylene copolymer substituted mono- or dicarboxylicacid material and amido-amine will be contacted for a time and underconditions sufficient to react substantially all of the primarynitrogens in the amido-amine reactant. The progress of this reaction canbe followed by infra-red analysis.

This reaction can be conducted in a polar or non-polar solvent, e.g.,xylene, toluene, benzene, and the like, and is preferably conducted inthe presence of a mineral or synthetic lubricating oil.

In aspect B of the instant invention the carboxylic acid materialgrafted ethylene copolymer, e.g., succinic anhydride graftedethylene-propylene copolymer, is reacted with the amido-amine and thecarboxylic acid component which is described more fully hereinafter. Inthe reaction involving the carboxylic acid material grafted ethylenecopolymer, amido-amine, and carboxylic acid component it is generallypreferred that a reaction mixture containing said carboxylic acidmaterial grafted ethylene copolymer and said carboxylic acid componentbe first prepared. This reaction mixture can be readily prepared byadmixing the carboxylic acid component and the carboxylic acid materialgrafted ethylene copolymer. Into this reaction mixture is thenintroduced the amido-amine. This amido-amine is then reacted with thecarboxylic acid material grafted ethylene copolymer and with thecarboxylic acid component to form the nitrogen containing carboxylicacid material grafted ethylene copolymer of the instant invention.

Alternatively, the amido-amine and the carboxylic acid component can beadded substantially simultaneously or concurrently to the carboxylicacid material grafted ethylene-propylene copolymer to form a reactionmixture. This reaction mixture is then reacted under conditionseffective for the three components to react and form the nitrogencontaining carboxylic acid material grafted ethylene copolymer of theinstant invention.

Furthermore, the carboxylic acid component and the amido-amine may beprereacted, and this prereacted carboxylic acid component/amido-aminemay then be coreacted with the carboxylic acid material grafted ethylenecopolymer to form the nitrogen containing carboxylic acid materialgrafted ethylene copolymer of the instant invention.

Carboxylic Acid Component

The carboxylic acid component includes: hydrocarbyl substituteddicarboxylic acid or anhydride, preferably succinic anhydride or acid,having 12 to 49 carbons, preferably I6 to 49 carbons in said hydrocarbylgroup; long chain monocarboxylic acid of the formula R¹⁰ COOH where R¹⁰is a hydrocarbyl group of 50 to 400 carbons and long chain hydrocarbylsubstituted dicarboxylic acid or anhydride, preferably succinicanhydride or acid, having from about 50 to about 400 carbons in saidhydrocarbyl group. The preferred carboxylic acid component is the longchain hydrocarbyl substituted dicarboxylic acid or anhydride, preferablysuccinic acid or anhydride, having from about 50 to about 400 carbonatoms in said hydrocarbyl group. Said hydrocarbyl groups are essentiallyaliphatic and include alkenyl and alkyl groups The longer chain acidsand anhydrides are preferred, particularly when the grafting reaction iscarried out in lubricating oil.

The about C₅₀ -C₄₀₀ hydrocarbyl substituted dicarboxylic acid oranhydride includes the reaction product of the C₅₀ -C₄₀₀ hydrocarbonpolymer, generally a polyolefin, with (i) monounsaturated C₄ to C₁₀dicarboxylic acid wherein (a) the carboxyl groups are vicinyl, i.e.,located on adjacent carbon atoms, and (b) at least one, preferably both,of said adjacent carbon atoms are part of said monounsaturation; or with(ii) derivatives of (i) such as anhydrides of (i). Upon reaction withthe hydrocarbon polymer, the monounsaturation of the dicarboxylic acid,anhydride, etc. becomes saturated. Thus for example, maleic anhydridebecomes a hydrocarbyl substituted succinic anhydride.

Typically, from about 0.7 to about 4.0 (e.g., 0.8 to 2.6), preferablyfrom about 1.0 to about 2.0, and most preferably from about 1.1 to about1.7 moles of said unsaturated C₄ to C₁₀ dicarboxylic acid, anhydride orester are charged to the reactor per mole of polyolefin charged.

Normally, not all of the polyolefin reacts with the unsaturated acid orderivative and the hydrocarbyl substituted dicarboxylic acid materialwill contain unreacted polyolefin. The unreacted polyolefin is typicallynot removed from the reaction mixture (because such removal is difficultand would be commercially infeasible) and the product mixture, strippedof any unreacted monounsaturated C₄ to C₁₀ dicarboxylic acid oranhydride, is employed as the carboxylic acid component.

Characterization of the average number of moles of dicarboxylic acid oranhydride, which have reacted per mole of polyolefin charged to thereaction (whether it has undergone reaction or not) is defined herein asfunctionality. Said functionality is based upon (i) determination of thesaponification number of the resulting product mixture using potassiumhydroxide; and (ii) the number average molecular weight of the polymercharged, using techniques well known in the art. Functionality isdefined solely with reference to the resulting product mixture. Althoughthe amount of said reacted polyolefin contained in the resulting productmixture can be subsequently modified, i.e., increased or decreased bytechniques known in the art, such modifications do not alterfunctionality as defined above. The term C₅₀ -C₄₀₀ hydrocarbylsubstituted dicarboxylic acid material is intended to refer to theproduct mixture whether it has undergone such modification or not.

Accordingly, the functionality of the C₅₀ -C₄₀₀ hydrocarbyl substituteddicarboxylic acid material will be typically at least about 0.5,preferably at least about 0.8, and most preferably at least about 0.9and will vary typically from about 0.5 to about 2.8 (e.g., 0.6 to 2),preferably from about 0.8 to about 1.4, and most preferably from about0.9 to about 1.3.

Exemplary of such unsaturated dicarboxylic acids or anhydrides thereofare fumaric acid, itaconic acid, maleic acid, maleic anhydride,chloromaleic acid, chloromaleic anhydride, etc.

Preferred about C₅₀ to about C₄₀₀ olefin polymers for reaction with theunsaturated dicarboxylic acids or derivatives thereof are polymerscomprising a major molar amount of C₂ to C₁₀, e.g., C₂ to C₅ monoolefin.Such olefins include ethylene, propylene, butylene, isobutylene,pentene, octene-1, styrene, etc. The polymers can be homopolymers suchas polyisobutylene, as well as copolymers of two or more of such olefinssuch as copolymers of: ethylene and propylene; butylene and isobutylene;propylene and isobutylene; etc. Other copolymers include those in whicha minor molar amount of the copolymer monomers, e.g., 1 to 10 mole %, isa C₄ to C₁₈ non-conjugated diolefin, e.g., a copolymer of isobutyleneand butadiene; or a copolymer of ethylene, propylene and 1,4-hexadiene;etc.

In some cases, the olefin polymer may be completely saturated, forexample an ethylene-propylene copolymer made by a Ziegler-Nattasynthesis using hydrogen as a moderator to control molecular weight.

The olefin polymers used will usually have number average molecularweights within the range of about 700 and about 5,600, more usuallybetween about 800 and about 3000. Particularly useful olefin polymershave number average molecular weights within the range of about 900 andabout 2500 with approximately one terminal double bond per polymerchain. An especially useful starting material is polyisobutylene. Thenumber average molecular weight for such polymers can be determined byseveral known techniques. A convenient method for such determination isby gel permeation chromatography (GPC) which additionally providesmolecular weight distribution information, see W. W. Yau, J. J. Kirklandand D. D. Bly, "Modern Size Exclusion Liquid Chromatography", John Wileyand Sons, New York, 1979.

Processes for reacting the about C₅₀ to about C₄₀₀ olefin polymer withthe C₄₋₁₀ unsaturated dicarboxylic acid or anhydride are known in theart. For example, the olefin polymer and the dicarboxylic acid orderivative may be simply heated together as disclosed in U.S. Pats. No.3,361,673 and 3,401,118 to cause a thermal "ene" reaction to take place.Or, the olefin polymer can be first halogenated, for example,chlorinated or brominated to about 1 to 8 wt. %, preferably 3 to 7 wt. %chlorine, or bromine, based on the weight of polymer, by passing thechlorine or bromine through the polyolefin at a temperature of 60° to250° C., e.g. 120° to 160° C., for about 0.5 to 10, preferably 1 to 7hours. The halogenated polymer may then be reacted with sufficientunsaturated acid or derivative at 100° to 250° C., usually about 180 to235° C., for about 0.5 to 10, e.g. 3 to 8 hours, so the product obtainedwill contain the desired number of moles of the unsaturated acid orderivative per mole of the halogenated polymer. Processes of thisgeneral type are taught in U.S. Pat. Nos. 3,087,936; 3,172,892;3,272,746 and others.

Alternatively, the olefin polymer, and the unsaturated acid orderivative are mixed and heated while adding chlorine to the hotmaterial. Processes of this type are disclosed in U.S. Pat. Nos.3,215,707; 3,231,587; 3,912,764; 4,110,349; and in U.K. 1,550,219.

By the use of halogen, about 65 to 95 wt. % of the polyolefin, e.g.polyisobutylene will normally reacted with the dicarboxylic acid orderivative. Upon carrying out a thermal reaction without the use ofhalogen or a catalyst, then usually only about 50 to 75 wt. % of thepolyisobutylene will react. Chlorination helps increased the reactivity.

Particularly preferred as the acid component is polyisobutenyl succinicanhydride.

PRE-REACTED AMIDO AMINE-CARBOXYLIC ACID COMPONENT

The aforesaid amido-amine and carboxylic acid component may bepre-reacted, with the acid being generally attached to the amido-aminethrough salt, imide, amide, or other linkages so that a primary orsecondary amine group of the amido-amine is still available for reactionwith the acid moieties of the grafted high molecular weight ethylenecopolymer. A convenient source of these pre-reacted materials are thelubricating oil dispersant, provided they retain primary amine groupscapable of further reaction with the grafted ethylene copolymer, such asthose described in U.S. application Ser. No. 126,405, filed Nov. 30,1987 and U.S. application Ser. No. 269,461, filed Nov. 10, 1988, both ofwhich are incorporated herein by reference.

The carboxylic acid material grafted ethylene copolymer is reacted withthe amido-amine and carboxylic acid component or pre-reactedamido-amine/carboxylic acid component substantially as describedhereinafore for the reaction of the carboxylic acid material graftedethylene copolymer with the amido-amine. Thus, for example a reactionmixture containing the grafted ethylene copolymer, e.g.,ethylene-propylene substituted succinic anhydride, and carboxylic acidcomponent, e.g., polyisobutenyl substituted succinic anhydride, isprepared by admixing these two reactants, and the amido-amine is thenintroduced into this reaction mixture and the reaction is carried out asdescribed hereinafore. Alternatively, the carboxylic acid component andamido-amine may be added substantially simultaneously to a reactionmixture containing the carboxylic acid material grafted ethylenecopolymer.

Generally, the amount of the carboxylic acid component utilized is anamount sufficient to provide about 0.5 to about 4, preferably from about1 to about 2 moles of said carboxylic acid component per molar amount ofthe carboxylic acid moieties present in the grafted ethylene copolymer.For example, with a grafted ethylene-propylene copolymer of about 40,000M_(n) and averaging 4 succinic anhydride groups per molecule, about 4moles of polyisobutenyl succinic anhydride would preferably be used permole of grafted copolymer. Generally, from about 1 to 5, preferably fromabout 1.5 to 3 moles of the combined carboxylic acid moiety content ofthe grafted ethylene copolymer and the carboxylic acid content are usedper equivalent of amido-amine reactant, e.g., amine.

Under certain conditions, particularly upon storage, oleaginouscompositions, particularly oil concentrates, containing themultifunctional viscosity index improver additives of the instantinvention may exhibit an increase in viscosity. This viscosity increaseappears to be due, at least in part, to chain extension and/orcross-linking of the nitrogen containing grafted ethylene copolymer ofthe instant invention. In order to stabilize the viscosity and retard orinhibit said viscosity increase of these oil compositions the nitrogencontaining grafted ethylene copolymers of the instant invention can betreated or post-reacted with a variety of materials, particularly acidmaterials, to inactivate the remaining reactive amino groups, i.e.,secondary amino groups or primary amino groups. This treatment prevents,diminishes, or retards chain-extension and/or crosslinking of thenitrogen containing grafted ethylene copolymer. Thus, for example, thenitrogen containing acid material grafted ethylene copolymer may bereacted or post-treated with C₁ -C₃₀ monocarboxylic acids or anhydrides,preferably acetic anhydride, or unsubstituted or C₁ to C₂₈ hydrocarbylsubstituted dicarboxylic acid anhydrides as disclosed in U.S. Pat. No.4,137,185, incorporated herein by reference; the sulfonic acids of U.S.Pat. No. 4,144,181, incorporated herein by reference; and the C₁₂ to C₁₈hydrocarbyl substituted dicarboxylic anhydrides, preferably C₁₂ to C₁₈hydrocarbyl substituted succinic anhydride, of U.S. Pat. No. 4,803,003,incorporated herein by reference.

Preferred viscosity stabilizing materials are those disclosed in U.S.Pat. No. 4,803,003, i.e., the C₁₂ to about C₁₈ hydrocarbyl substituteddicarboxylic anhydrides. These anhydrides may be represented by thegeneral formula R¹¹ Y wherein R¹¹ is a hydrocarbyl group containing atotal of from 12 to about 18, preferably 12 to 16, more preferably 12 to14, and most preferably 12 carbons, which are essentially aliphatic,saturated or unsaturated, and include alkenyl groups, alkyl groups, andmixtures of alkenyl groups and alkyl groups, preferably alkenyl groups,and can be straight chain or branched, and Y is a dicarboxylic anhydridemoiety. When R¹¹ is an alkenyl group it is preferred that the olefinicunsaturation site be located near the anhydride, e.g., allylic to Y,moiety. The radical Y will usually contain 4 to 10, preferably 4 to 8,more preferably 4 to 6, and most preferably 4 carbon atoms and willdefine a dicarboxylic anhydride. The Y radical may be represented by theformula ##STR28## wherein Z is selected from alkylene and alkenyleneradicals containing from 2 to 8, preferably 2 to 6, more preferably 2 to4, and most preferably 2 carbon atoms. Preferably Z is an alkyleneradical. The most preferred Y radical is the succinic anhydride radical,i.e., ##STR29## The Y radical is linked to the R¹¹ group by a carbon tocarbon linkage.

The amount of the hydrocarbyl substituted dicarboxylic anhydrideutilized is a viscosity stabilizing effective amount. By viscositystabilizing effective amount is meant any amount which is effective tostabilize the viscosity of an oleaginous solution of the nitrogencontaining acid material grafted ethylene copolymers, i.e., inhibit orreward the increase in viscosity over an extended period of time of anoil solution, particularly an oil concentrate, of the nitrogencontaining grafted ethylene copolymers. Generally this amount is fromabout 0.5-2.5, preferably 1-1.5 moles of C₁₂ to about C₁₈ hydrocarbylsubstituted dicarboxylic anhydride per mole of any remaining primary orsecondary amino groups of the ethylene copolymer grafted with acarboxylic acid material and thereafter reacted with the amido-amine.

The chain extension termination or end-capping of the nitrogencontaining grafted ethylene copolymer which was preferentially preparedin a mineral oil solution can be conducted by subsequently introducingthe C₁₂ to about C₁₈ hydrocarbyl substituted dicarboxylic anhydridedirectly into the reaction system used to prepare said nitrogencontaining grafted ethylene copolymer, or it can be a separatenon-integrated reaction step. Generally, the nitrogen containingcarboxylic acid material grafted ethylene copolymer is first produced bypreparing the grafted ethylene copolymer and then reacting this graftedcopolymer with at least one amido-amine, or with the carboxylic acidcomponent and amido-amine, or with the preformed carboxylic acidcomponent and amido-amine, and this nitrogen containing grafted ethylenecopolymer is then subsequently reacted or treated with the C₁₂ to aboutC₁₈ hydrocarbyl substituted dicarboxylic anhydride in a end-capping orchain extension limiting step A viscosity stabilizing effective amountof the C₁₂ to about C₁₈ hydrocarbyl substituted dicarboxylic anhydrideis introduced into the heated solution containing the nitrogen or estercontaining grafted ethylene copolymer and the reaction carried on for aperiod of about 0.25 to 8 hours at a temperature of about 100° to 200°C. being preferred. In order to fully complete the reaction, it isgenerally useful to utilize a slight excess, i.e., about 1 to 30, moreusually about 1 to 10, percent by weight of the C₁₂ to about C₁₈hydrocarbyl substituted dicarboxylic anhydride. The entire reaction isgenerally carried out under an inert atmosphere, for example, a nitrogenblanket.

This reaction can be conducted in a polar or non-polar solvent, e.g.,xylene, toluene, benzene, and the like, and is preferably conducted inthe presence of a mineral or synthetic lubricating oil.

Alternatively, at least a portion of the C₁₂ to C₁₈ hydrocarbylsubstituted dicarboxylic anhydride or other end-capping agent can beintroduced into a reaction mixture containing the carboxylic acidmaterial grafted ethylene copolymer prior to or concurrently with theintroduction of the amido-amine reactant, and the remaining portion ofthe end-capping agent can be reacted with the preformed, partiallyend-capped nitrogen containing grafted ethylene copolymer.

The nitrogen containing grafted ethylene copolymers, i.e., thederivatized ethylene copolymers, of the instant invention, eitherunreacted or reacted with the viscosity stabilizing or end-cappingagents described hereinafore, may optionally be post-treated bycontacting said nitrogen containing acid material grafted ethylenecopolymer with one or more post-treating reagents selected from thegroup consisting of boron oxide, boron oxide hydrate, boron halides,boron acids, esters of boron acids, carbon disulfide, sulfur, sulfurchlorides, alkenyl cyanides, aldehydes, ketones, urea, thio-urea,guanidine, dicyanodiamide, hydrocarbyl phosphates, hydrocarbylphosphites, hydrocarbyl thiophosphates, hydrocarbyl thiophosphites,phosphorus sulfides, phosphorus oxides, phosphoric acid, hydrocarbylthiocyanates, hydrocarbyl isocyanates, hydrocarbyl isothiocyantes,epoxides, episulfides, formaldehyde or formaldehyde-producing compoundsplus phenols, and sulfur plus phenols.

Since post-treating processes involving the use of these post-treatingreagents are known insofar as application to reaction products of highmolecular weight carboxylic acid acylating agents of the priordisclosures and amines and/or alcohols, detailed descriptions of theseprocesses herein is unnecessary. In order to apply these processes tothe compositions of this invention, all that is necessary is thatreaction conditions, ratio of reactants, and the like as described inthese prior disclosure processes, be applied to the novel compositionsof this invention. The following U.S. patents are expressly incorporatedherein by reference for their disclosure of post-treating processes andpost-treating reagents applicable to the compositions of this invention:U.S. Pat. Nos. 3,087,936; 3,200,107; 3,254,025; 3,256,185; 3,278,550;3,281,428; 3,282,955; 3,284,410; 3,338,832, 3,344,069; 3,366,569;3,373,111; 3,367,943; 3,403,102; 3,428,561; 3,502,677; 3,513,093;3,533,945; 3,541,012 (use of acidified clays in post-treating carboxylicderivative compositions derived from the acrylating reagents of thisinvention and amines); 3,639,242; 3,708,522; 3,859,318; 3,865,813;3,470,098; 3,369,021; 3,184,411; 3,185,645; 3,245,908; 3,245,909;3,245,910; 3,573,205; 3,692,681; 3,749,695; 3,865,740; 3,954,639;3,458,530; 3,390,086; 3,367,943; 3,185,704, 3,551,466; 3,415,750;3,312,619; 3,280,034; 3,718,663; 3,652,616; UK Pat. No. 1,085,903; UKPat. NO. 1,162,436; U.S. Pat. No. 3,558,743. The processes of theseincorporated patents, as applied to the compositions of this invention,and the post-treated compositions thus produced constitute a furtheraspect of this invention.

A minor amount, e.g. 0.01 up to 49 wt %, preferably 0.05 to 25 wt. %,based on the weight of the total composition, of the V.I.improver-dispersants produced in accordance with this invention can beincorporated into a major amount of an oleaginous material, such as alubricating oil or hydrocarbon fuel, depending upon whether one isforming finished products or additive concentrates. When used inlubricating oil compositions, e.g. automotive or diesel crankcaselubricating oil, derivatized copolymer concentrations are usually withinthe range of about 0.01 to 25 wt %, of the total composition. Thelubricating oils to which the products of this invention can be addedinclude not only hydrocarbon oil derived from petroleum, but alsoinclude synthetic lubricating oils such as esters of dibasic acids;complex esters made by esterifications of monobasic acids, polyglycols,dibasic acids and alcohols; polyolefin oils, etc.

The nitrogen containing acid material grafted ethylene copolymer of theinvention may be utilized in a concentrate form, e.g., from about 5 wt %up to about 49 wt. %, preferably 7 to 25 wt. %, in oil, e.g., minerallubricating oil, for ease of handling, and may be prepared in this formby carrying out the reaction of the invention in oil as previouslydiscussed.

The above oil compositions may optionally contain other conventionaladditives, pour point depressants, antiwear agents, antioxidants, otherviscosity-index improvers, dispersants, corrosion inhibitors,anti-foaming agents, detergents, rust inhibitors, friction modifiers,and the like.

Corrosion inhibitors, also known as anti-corrosive agents, reduce thedegradation of the metallic parts contacted by the lubricating oilcomposition. Illustrative of corrosion inhibitors are phosphosulfurizedhydrocarbons and the products obtained by reaction of aphosphosulfurized hydrocarbon with an alkaline earth metal oxide orhydroxide, preferably in the presence of an alkylated phenol or of analkylphenol thioester, and also preferably in the presence of carbondioxide. Phosphosulfurized hydrocarbons are prepared by reacting asuitable hydrocarbon such as a terpene, a heavy petroleum fraction of aC₂ to C₆ olefin polymer such as polyisobutylene, with from 5 to 30 wt. %of a sulfide of phosphorus for 1/2 to 15 hours, at a temperature in therange of about 66 to about 316° C. Neutralization of thephosphosulfurized hydrocarbon may be effected in the manner taught inU.S. Pat. No. 1,969,324.

Oxidation inhibitors, or antioxidants, reduce the tendency of mineraloils to deteriorate in service which deterioration can be evidenced bythe products of oxidation such as sludge and varnish-like deposits onthe metal surfaces, and by viscosity growth. Such oxidation inhibitorsinclude alkaline earth metal salts of alkylphenolthioesters havingpreferably C₅ to C₁₂ alkyl side chains, e.g., calcium nonylphenolsulfide, barium toctylphenyl sulfide, dioctylphenylamine,phenylalphanaphthylamine, phospho- sulfurized or sulfurizedhydrocarbons, etc.

Other oxidation inhibitors or antioxidants useful in this inventioncomprise oil-soluble copper compounds. The copper may be blended intothe oil as any suitable oil-soluble copper compound. By oil soluble itis meant that the compound is oil soluble under normal blendingconditions in the oil or additive package. The copper compound may be inthe cuprous or cupric form. The copper may be in the form of the copperdihydrocarbyl thio- or dithio-phosphates. Alternatively, the copper maybe added as the copper salt of a synthetic or natural carboxylic acid.Examples of same thus include C₁₀ to C₁₈ fatty acids, such as stearic orpalmitic acid, but unsaturated acids such as oleic or branchedcarboxylic acids such as napthenic acids of molecular weights of fromabout 200 to 500, or synthetic carboxylic acids, are preferred, becauseof the improved handling and solubility properties of the resultingcopper carboxylates. Also useful are oil-soluble copper dithiocarbamatesof the general formula (RR,NCSS)nCu (where n is 1 or 2 and R and R, arethe same or different hydrocarbyl radicals containing from to 18, andpreferably 2 to 12, carbon atoms, and including radicals such as alkyl,alkenyl, aryl, aralkyl, alkaryl and cycloaliphatic radicals.Particularly preferred as R and R, groups are alkyl groups of from 2 to8 carbon atoms. Thus, the radicals may, for example, be ethyl, n-propyl,i-propyl, n-butyl, i-butyl, sec-butyl, amyl, n-hexyl, i-hexyl, n-heptyl,n-octyl, decyl, dodecyl, octadecyl, 2-ethylhexyl, phenyl, butylphenyl,cyclohexyl, methylcyclopentyl, propenyl, butenyl, etc. In order toobtain oil solubility, the total number of carbon atoms (i.e., R and R,)will generally be about 5 or greater. Copper sulphonates, phenates, andacetylacetonates may also be used.

Exemplary of useful copper compounds are copper CuI and/or CuII salts ofalkenyl succinic acids or anhydrides. The salts themselves may be basic,neutral or acidic. They may be formed by reacting (a) polyalkylenesuccinimides (having polymer groups of M_(n) of 700 to 5,000) derivedfrom polyalkylene-polyamines, which have at least one free carboxylicacid group, with (b) a reactive metal compound. Suitable reactive metalcompounds include those such as cupric or cuprous hydroxides, oxides,acetates, borates, and carbonates or basic copper carbonate.

Examples of these metal salts are Cu salts of polyisobutenyl succinicanhydride, and Cu salts of polyisobutenyl succinic acid. Preferably, theselected metal employed is its divalent form, e.g., Cu+2. The preferredsubstrates are polyalkenyl succinic acids in which the alkenyl group hasa molecular weight greater than about 700. The alkenyl group desirablyhas a M_(n) from about 900 to 1,400, and up to 2,500, with a M_(n) ofabout 950 being most preferred. Especially preferred is polyisobutylenesuccinic anhydride or acid. These materials may desirably be dissolvedin a solvent, such as a mineral oil, and heated in the presence of awater solution (or slurry) of the metal bearing material. Heating maytake place between 70° and about 200° C. Temperatures of 110° C. to 140°C. are entirely adequate. It may be necessary, depending upon the saltproduced, not to allow the reaction to remain at a temperature aboveabout 140° C. for an extended period of time, e.g., longer than 5 hours,or decomposition of the salt may occur.

The copper antioxidants (e.g., Cu-polyisobutenyl succinic anhydride,Cu-oleate, or mixtures thereof) will be generally employed in an amountof from about 50 to 500 ppm by weight of the metal, in the finallubricating or fuel composition.

Friction modifiers serve to impart the proper friction characteristicsto lubricating oil compositions such as automatic transmission fluids.

Representative examples of suitable friction modifiers are found in U.S.Pat. No. 3,933,659 which discloses fatty acid esters and amides; U.S.Pat. No. 4,176,074 which describes molybdenum complexes ofpolyisobutenyl succinic anhydride-amino alkanols; U.S. Pat. No.4,105,571 which discloses glycerol esters of dimerized fatty acids; U.S.Pat. No. 3,779,928 which discloses alkane phosphonic acid salts; U.S.Pat. No. 3,778,375 which discloses reaction products of a phosphonatewith an oleamide; U.S. Pat. No. 3,852,205 which disclosesS-carboxyalkylene hydrocarbyl succinimide, S-carboxyalkylene hydrocarbylsuccinamic acid and mixtures thereof; U.S. Pat. No. 3,879,306 whichdiscloses N(hydroxyalkyl)alkenyl-succinamic acids or succinimides; U.S.Pat. No. 3,932,290 which discloses reaction products of di- (loweralkyl) phosphites and epoxides; and U.S. Pat. No. 4,028,258 whichdiscloses the alkylene oxide adduct of phosphosulfurizedN-(hydroxyalkyl) alkenyl succinimides. The disclosures of the abovereferences are herein incorporated by reference. The most preferredfriction modifiers are succinate esters, or metal salts thereof, ofhydrocarbyl substituted succinic acids or anhydrides andthiobis-alkanols such as described in U.S. Pat. No. 4,344,853.

Dispersants maintain oil insolubles, resulting from oxidation duringuse, in suspension in the fluid thus preventing sludge flocculation andprecipitation or deposition on metal parts. Suitable dispersants includehigh molecular weight alkyl succinimides, the reaction product ofoil-soluble polyisobutylene succinic anhydride with ethylene amines suchas tetraethylene pentamine and borated salts thereof.

Pour point depressants, otherwise known as lube oil flow improvers,lower the temperature at which the fluid will flow or can be poured.Such additives are well known. Typically of those additives whichusefully optimize the low temperature fluidity of the fluid are C₈ -C₁₈dialkylfumarate vinyl acetate copolymers, polymethacrylates, and waxnaphthalene. Foam control can be provided by an antifoamant of thepolysiloxane type, e.g., silicone oil and polydimethyl siloxane.

Anti-wear agents, as their name implies, reduce wear of metal parts.Representatives of conventional antiwear agents are zincdialkyldithiophosphate and zinc diaryldithiosphate.

Detergents and metal rust inhibitors include the metal salts ofsulphonic acids, alkyl phenols, sulfurized alkyl phenols, alkylsalicylates, naphthenates and other oil soluble mono- and dicarboxylicacids. Highly basic (viz, overbased) metal sales, such as highly basicalkaline earth metal sulfonates (especially Ca and Mg salts) arefrequently used as detergents. Representative examples of suchmaterials, and their methods of preparation, are found in co-pendingSerial No. 754,001, filed July 11, 1985, the disclosure of which ishereby incorporated by reference.

Some of these numerous additives can provide a multiplicity of effects,e.g., a dispersant-oxidation inhibitor. This approach is well known andneed not be further elaborated herein.

Compositions when containing these conventional additives are typicallyblended into the base oil in amounts which are effective to providetheir normal attendant function. Representative effective amounts ofsuch additives are illustrated as follows:

    ______________________________________                                                          Wt. % a.i.                                                                              Wt. % a.i.                                        Additive          (Broad)   (Preferred)                                       ______________________________________                                        Viscosity Modifier                                                                               .01-12   .01-4                                             Corrosion Inhibitor                                                                             0.01-5    .01-1.5                                           Oxidation Inhibitor                                                                             0.01-5    .01-1.5                                           Dispersant         0.1-20   0.1-8                                             Pour Point Depressant                                                                           0.01-5    .01-1.5                                           Anti-Foaming Agents                                                                             0.001-3   .001-0.15                                         Anti-Wear Agents  0.001-5   .001-1.5                                          Friction Modifiers                                                                              0.01-5    .01-1.5                                           Detergents/Rust Inhibitors                                                                       .01-10   .01-3                                             Mineral Oil Base  Balance   Balance                                           ______________________________________                                    

When other additives are employed, it may be desirable, although notnecessary, to prepare additive concentrates comprising concentratedsolutions or dispersions of the dispersant (in concentrate amountshereinabove described), together with one or more of said otheradditives (said concentrate when constituting an additive mixture beingreferred to here in as an additive package) whereby several additivescan be added simultaneously to the base oil to form the lubricating oilcomposition. Dissolution of the additive concentrate into thelubricating oil may be facilitated by solvents and by mixing accompaniedwith mild heating, but this is not essential. The concentrate oradditive-package will typically be formulated to contain the dispersantadditive and optional additional additives in proper amounts to providethe desired concentration in the final formulation when theadditive-package is combined with a predetermined amount of baselubricant. Thus, the products of the present invention can be added tosmall amounts of base oil or other compatible solvents along with otherdesirable additives to form additive-packages containing activeingredients in collective amounts of typically from about 2.5 to about90%, and preferably from about 5 to about 75%, and most preferably fromabout 8 to about 50% by weight additives in the appropriate proportionswith the remainder being base oil.

The final formulations may employ typically about 10 wt. % of theadditive-package with the remainder being base oil.

All of said weight percents expressed herein are based on activeingredient (a.i.) content of the additive, and/or upon the total weightof any additive-package, or formulation which will be the sum of thea.i. weight of each additive plus the weight of total oil or diluent.

As mentioned hereinafore, the nitrogen containing acid material graftedethylene copolymers of the present invention are particularly useful asfuel and lubricating oil additives.

The nitrogen containing grafted ethylene copolymers of this inventionfind their primary utility, however, in lubricating oil compositions,which employ a base oil in which these copolymers are dissolved ordispersed.

Thus, base oils suitable for use in preparing the lubricatingcompositions of the present invention include those conventionallyemployed as crankcase lubricating oils for spark-ignited andcompression-ignited internal combustion engines, such as automobile andtruck engines, marine and railroad diesel engines, and the like.Advantageous results are also achieved by employing the additives of thepresent invention in base oils conventionally employed in and/or adaptedfor use as power transmitting fluids such as automatic transmissionfluids, tractor fluids, universal tractor fluids and hydraulic fluids,heavy duty hydraulic fluids, power steering fluids and the like. Gearlubricants, industrial oils, pump oils and other lubricating oilcompositions can also benefit from the incorporation therein of theadditives of the present invention.

Thus, the additives of the present invention may be suitablyincorporated into synthetic base oils such as alkyl esters ofdicarboxylic acids, polyglycols and alcohols; polyalpha-olefins,polybutenes, alkyl benzenes, organic esters of phosphoric acids,polysilicone oils, etc.

The nitrogen containing carboxylic acid material grafted ethylenecopolymers of the instant invention are oil-soluble, dissolvable in oilwith the aid of a suitable solvent, or are stably dispersible therein.The terms oil-soluble, dissolvable in oil, or stably dispersible in oilas that terminology is used herein does not necessarily indicate thatthe materials are soluble, dissolvable, miscible, or capable of beingsuspended in oil in all proportions. It does mean, however, that theadditives for instance, are soluble or stably dispersible in oil to anextent sufficient to exert their intended effect in the environment inwhich the oil is employed. Moreover, the additional incorporation ofother additives may also permit incorporation of higher levels of aparticular copolymer hereof, if desired.

Accordingly, while any effective amount, i.e., dispersant or viscosityindex improving--dispersant effective amount, of the additives of thepresent invention can be incorporated into the fully formulatedlubricating oil composition, it is contemplated that such effectiveamount be sufficient to provide said lube oil composition with an amountof the additive of typically from about 0.001 to about 20, preferablyabout 0.01 to about 15, more preferably from about 0.1 to about 10, andmost preferably from about 0.25 to about 5.0 wt. %, based on the weightof said composition.

The following examples are presented to further illustrate the instantinvention. These examples are presented by way of illustration and donot limit the instant invention thereto. Unless otherwise indicated allparts and percentages are parts and percentages are by weight.

Example 1 illustrates the preparation of an ethylene-propylene copolymerof the instant invention.

EXAMPLE 1

An ethylene-propylene copolymer having an ethylene content of about 56wt. %, a thickening efficiency (T.E.) of about 2.5, an M_(w) of about134,000, an M_(n) of about 85,000 a M_(w) /M_(n) of 1.58 and a M_(z)/M_(w) of 1.41 is prepared in a tubular reactor under the followingconditions:

    ______________________________________                                        Reactor Inlet Temp (°F.)                                                                    -4                                                       Reactor Outlet Temp (°F.)                                                                   57                                                       Sidestream Feed Temp.(°F.)                                                                  -26                                                      Catalyst Premix Temp (°F.)                                                                  91                                                       Catalyst Premix Time (Sec.)                                                                        7.87                                                     Reactor Residence Time (Sec.)                                                                      1.26/1.40                                                at Sidestream 1/2                                                             Inlet Feed Rates (Klb./hr.)                                                   Hexane               164.8                                                    Ethylene             1.03                                                     Propylene            15.36                                                    VCl.sub.4            0.03375                                                  Al.sub.2 (C.sub.2 H.sub.5).sub.3 Cl.sub.3                                                          0.861                                                    Sweep Hexane         4.926                                                    Sidestream Feed Rates (Klb./hr.)                                              Hexane               25                                                       Ethylene             3.02                                                     Propylene            5.84                                                     Total Hexane (Klb./hr.)                                                                            194.7                                                    Sidestream Feed Splits (wt. %)                                                                     70/30                                                    Sidestream 1/2                                                                ______________________________________                                    

Example 2 illustrates the preparation of an amido-amine of the instantinvention.

EXAMPLE 2

Into a 500 ml. four neck reaction flask, fitted with a stirrer,thermometer and addition funnel are charged 158 grams (2.63 mole) ofethylenediamine. Nitrogen is introduced into the flask to provide anitrogen blanket. 113.23 grams (1.32 mole) of methyl acrylate are addedslowly via the addition funnel so as to keep the temperature of thereaction mixture below 40° C. After addition of the methyl acrylate iscomplete the reaction mixture is stirred for one hour. The temperatureis then raised to 100° C. and the reaction mixture is kept at thistemperature for 3 hours. The reaction mixture is then allowed to cool to40° C. The reaction mixture is stripped to remove methanol byproduct.The reaction mixture is then heated at 110° C. for one hour. Thereaction mixture is then allowed to cool to 50° C. and is stripped for11/2 hours.

Example 3 illustrates the preparation of a succinic anhydride graftedethylene-propylene copolymer.

EXAMPLE 3

Twenty four pounds of ethylene-propylene copolymer preparedsubstantially in accordance with the procedure of Example 1 aredissolved in 136 pounds of S100 NLP mineral oil at 175° C. undernitrogen atmosphere. To this solution are charged 3 pounds of maleicanhydride in 4 equal portions, each charge being 22 minutes apart, while0.66 pounds of di-t-butyl peroxide are charged to the reaction mixtureover a 90 minute period.

At the end of the di-t-butyl peroxide addition, the reaction mixture issoaked for about 30 minutes. The reaction mixture is then stripped withnitrogen for 1.5 hours to remove unreacted maleic anhydride from thereaction mixture. The total acidity of the reaction mixture isdetermined to be 0.16 meg./gram of sample. The grafted copolymer has aM_(n) of 89,000, a M_(w) /M_(n) of 1.45, and a M_(z) /M_(w) of 1.27.

Example 4 illustrates the preparation of the nitrogen containingsuccinic anhydride grafted ethylene-propylene copolymer of the instantinvention.

EXAMPLE 4

Into a reactor vessel are charged 205 grams of the reaction productExample 3 and heated to 175° C. under nitrogen atmosphere. To thisreaction mixture are added 37.7 grams of an 80 wt % solution in S100 NLPmineral oil of polyisobutenyl succinic anhydride (having a functionalityof about 1.05, a polyisobutene M_(n) of about 95°, a saponificationNumber of about 112, and containing about 12% unreacted polyisobutene).The reaction mixture is then stripped with nitrogen for 1/2 hour. Aftercompletion of nitrogen stripping 6.07 grams of the amido-amine ofExample 2 are added to the reaction mixture over a 20 minute period,followed by nitrogen stripping of the reaction mixture for 40 minutes.Then 2.04 grams of dodecynl succinic anhydride are added to the reactionmixture and the reaction mixture is soaked for 1/2 hour. The reactionmixture is then diluted with S100 NLP mineral oil to about a 9.2%polymer content. The Thickening Efficiency (T.E.) of the reactionproduct is 2.92.

The following Comparative Example illustrates a nitrogen containingsuccinic anhydride grafted ethylene-propylene copolymer falling outsidethe scope of the instant invention.

COMPARATIVE EXAMPLE 5

A conventional ethylene propylene copolymer falling outside the scope ofthe instant invention having a M_(w) of 121,000, a M_(n) of 41,000, aM_(z) /M_(n) of 2.93, and a M_(z) /M_(w) of 2.39 grafted with maleicanhydride substantially in accordance with the procedure of Example 3.The total acidity of the reaction product mixture is 0.14 mg./gram ofsample. The succinic anhydride grafted ethylene-propylene copolymer isthen reacted with the amido-amine of Example 2 substantially inaccordance with the procedure of Example 4.

EXAMPLE 6

A series of lubricating oil compositions formulated to 10W40specifications and containing a heavy duty detergent inhibitor packageand various amounts, as indicated in Table I, of the reaction productsof Example 3 4 and Comparative Example 5, are prepared by conventionaland well known methods.

The Kinematic Viscosity (KV) at 100° C., in centistokes (cst), and ColdCranking Simulator (CCS) viscosity at -20° C., in centipoise (cp) ofthese fully formulated oil compositions are determined and the resultsare set forth in Table I.

CCS (Cold Cranking Simulator), using a technique described inASTM-D2602, is a high shear viscosity measurement in centipoise. Thistest is related to a lubricating oil's resistance to cold enginestarting.

Additionally, the Shear Stability Index (SSI), in %, of the nitrogencontaining succinic anhydride grafted ethylene-propylene copolymers ofExample 4 and Comparative Example 5 are determined and the results arealso set forth in Table I. Shear Stability Index (SSI) measures themechanical stability of polymers used as V.I. improvers in crankcaselubricants subjected to high strain rates. The diesel fuel injector testwas used (CEC L-14-A-79, equivalent to DIN 51382). To determine SSI thepolymer under test is dissolved in a suitable base oil (for example, asolvent extracted 150 neutral) to a relative viscosity of 2 to 3 at 100°C. The oil solution is then circulated through a diesel fuel injector,for a total of thirty passes. The SSI is calculated from the initial100° C. kinematic viscosity (V_(i)), the final kinematic viscosity(V_(f)), and the base oil viscosity (V_(b)), as SSI (%)=100×(V_(i)-V_(f))/(V_(i) -V_(b)). A reference sample (as required by the DINmethod) is used to calibrate the test. The SSI is indicative of theresistance of a polymer to molecular weight degradation by extensionalforces. The higher the SSI the less stable the polymer, i.e., the moresusceptible it is to molecular weight degradation.

Furthermore, Thickening Efficiency (T.E.), as used herein, is defined asthe ratio of the weight percent of a polyisobutylene (sold as an oilsolution by Exxon Chemical Co. as Paratone N), having a StaudingerMolecular Weight of 20,000, required to thicken a solvent-extractedneutral mineral lubricating oil, having a viscosity of 150 SUS at 37.8°C., a viscosity index of 105 and an ASTM pour point of 0° F., (Solvent150 Neutral) to a viscosity of 12.4 centistokes at 98.9° C., to theweight percent of a test copolymer required to thicken the same oil tothe same viscosity at the same temperature. T.E. 5 related to M_(w) orM_(v) and is a convenient, useful measurement for formulation oflubricating oils of various grades.

                  TABLE I                                                         ______________________________________                                                     Amount of                                                                     Additive     KV      SSI  CCS                                    Additive     wt. % (polymer)                                                                            cst     %    cp                                     ______________________________________                                        Example 4    1.10         14.0    50   2577                                   COMPARATIVE  1.18         14.3    52   3033                                   Example 5                                                                     ______________________________________                                    

As illustrated by the data in Table I lubricating oil compositionscontaining the nitrogen containing succinic anhydride gratedthylene-propylene copolymers of the instant invention (Example 4)exhibit better low temperature viscometric properties (CCS) than thelubricating oil composition containing a conventional nitrogencontaining succinic anhydride grafted ethylene-propylene copolymerfalling outside the scope of the instant invention (Comparative Example5).

Furthermore, comparison of the Shear Stability Index of the nitrogencontaining succinic anhydride grafted ethylene-propylene copolymers ofthe instant invention (Example 4) with the Shear Stability Index of theconventional nitrogen containing succinic anhydride graftedethylene-propylene copolymer falling outside the scope of the instantinvention (Comparative Example 5) shows that the instant materials aremore Shear Stable, i.e., exhibit better mechanical properties, than theconventional materials falling outside the scope of the instantinvention.

What is claimed is:
 1. Composition of matter comprising reaction productof:(i) (a) from 1 to 5 moles of a copolymer of ethylene and at least oneother alpha-olefin monomer, said copolymer comprising intramolecularlyheterogeneous copolymer chains containing at least one crystallizablesegment of methylene units and at least one low crystallinityethylene-alpha-olefin copolymer segment, wherein said at least onecrystallizable segment comprises at least about 10 weight percent ofsaid copolymer chain and contains at least about 57 weight percentethylene, wherein said low crystallinity segment contains not greaterthan about 53 weight percent ethylene, and wherein said copolymer has amolecular weight distribution characterized by at least one of a ratioof Mw/Mn of less than 2 and a ratio of Mz/Mw of less than 1.8, andwherein at least two portions of an individual intramolecularlyheterogeneous chain, each portion comprising at least 5 weight percentof said chain, differ in composition from one another by at least 7weight percent ethylene, said copolymer grafted with (b) from about 0.7to 4.0 moles of ethylenically monounsaturated carboxylic acid materialhaving 1 or 2 carboxylic acid groups or anhydride group per mole ofcopolymer to form grafted ethylene copolymer; and (ii) one moleamido-amine comprising reaction product obtained by heating thefollowing mixture of (a) from about 1 to 10 equivalents of polyamine,based upon the primary amine content of said polyamine and (b) one moleof an alpha, beta unsaturated compound represented by the formula##STR30## wherein X is oxygen, Y is --OR⁴ or ##STR31## and R¹, R², R³,R⁴ and R⁵ are independently selected from hydrogen, hydrocarbyl, andsubstituted hydrocarbyl.
 2. The composition of matter according to claim1 wherein aid polyamine (ii)(a) comprises polyamines containing from 2to about 60 carbon atoms and from 2 to about 12 nitrogen atoms permolecule.
 3. The composition of matter according to claim 2 wherein saidpolyamine (ii)(a) comprises alkylenepolyamine or polyalkylenepolyaminewherein each alkylene group contains 2 to 6 carbons and saidalkylenepolyamine or polyalkylenepolyamine contains from 2 to about 5nitrogen atoms per molecule.
 4. The composition of matter according toclaim 1 wherein said monounsaturated carboxylic acid material (i)(b) isselected from the group consisting of C₄ to C₁₀ monounsaturateddicarboxylic acid material, C₃ to C₁₀ monounsaturated monocarboxylicacid material, and mixtures thereof.
 5. The composition of matteraccording to claim 4 wherein said monounsaturated carboxylic acidmaterial (i)(b) comprises monounsaturated C₃ to C₁₀ monocarboxylic acid.6. The composition of matter according to claim 4 wherein saidmonounsaturated carboxylic acid material (i)(b) comprises C₄ to C₁₀monounsaturated dicarboxylic acid material.
 7. The composition of matteraccording to claim 6 wherein said C₄ to C₁₀ monounsaturated dicarboxylicacid material is selected from the group consisting of maleic anhydride,maleic acid, and mixtures thereof.
 8. The composition of matteraccording to claim 7 wherein said C₄ to C₁₀ monounsaturated dicarboxylicacid material is maleic anhydride.
 9. The composition of matteraccording to claim 3 wherein said monounsaturated carboxylic acidmaterial (i)(b) comprises C₄ to C₁₀ monounsaturated dicarboxylic acidsor anhydrides.
 10. The composition of matter according to claim 9,wherein said C₄ to C₁₀ monounsaturated dicarboxylic acids or anhydridesare selected from the group consisting of maleic acid, maleic anhydride,and mixtures thereof.
 11. The composition of matter according to claim 1wherein said alpha-, beta-unsaturated compound (ii)(b) comprises atleast one member selected from the group consisting of methyl acrylate,ethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate,ethyl methacrylate, propyl methacrylate, and butyl methacrylate.
 12. Thecomposition of matter according to claim 11 wherein said polyamine(ii)(a) comprises alkylenepolyamine or polyalkylenepolyamine whereineach alkylene group contains 2 to 6 carbons and said alkylenepolyamineor polyalkylenepolyamine contains from 2 to about 5 nitrogen atoms permolecule.
 13. The composition of matter according to claim 12 whereinsaid polyamine (ii)(a) comprises ethylenepolyamine, propylenepolyamine,polyethylenepolyamine or, polypropylenepolyamine.
 14. The composition ofmatter according to claim 12 wherein said polyamine contains at least 2primary amino groups per molecule.
 15. The composition of matteraccording to claim 14 wherein from about 3 to about 5 equivalents ofsaid polyamine (ii)(a) based on said primary amine content thereof, arereacted per mole of said alpha, beta-unsaturated compound (ii)(b). 16.The composition of matter according to claim 15 wherein said amido-aminecontains an average of from 1 to 3 amido groups per molecule.
 17. Thecomposition of matter according to claim 16 wherein said monounsaturatedcarboxylic acid material (i)(b) comprises maleic anhydride.
 18. Thecomposition of matter according to claim 17 wherein from about 3 to 5equivalents of said amine (ii)(a), based on said primary amine contentthereof are reacted per mole of said alpha, beta- unsaturated compound(ii)(b).
 19. The composition of matter according to claim 18 whereinsaid amido-amine contains an average of from 1 to 3 thioamido groups permolecule.
 20. The composition of matter according to claim 1 whereinsaid copolymer (i)(a) has an intermolecular compositional dispersitysuch that 95 weight % of said copolymer chains have a composition 15weight % or less different from said average ethylene composition. 21.The composition of matter according to claim 30 wherein saidintermolecular compositional dispersity of said copolymer (i)(a) is suchthat 95 weight % of said copolymer chains have a composition 10 wt. % orless different from said average ethylene composition.
 22. Thecomposition of matter according to claim 1, wherein said lowcrystallinity segment of said copolymer (i)(a) comprises from about 20to 53 wt. % ethylene.
 23. The composition of matter according to claim22 wherein said crystallizable segment comprises at least about 57 wt. %ethylene.
 24. The composition of matter according to claim 23 whereinsaid copolymer (i)(a) is characterized by a weight-average molecularweight of from about 20,000 to about 250,000.
 25. The composition ofmatter according to claim 1 wherein said copolymer (i)(a) has a MWDcharacterized by at least one of a ratio of M_(w) /M_(n) of less thanabout 1.5 and a ratio of M_(z) /M_(w) of less than about 1.5.
 26. Thecomposition of matter according to claim 25 wherein said copolymer(i)(a) has a MWD characterized by at least one of a ratio of M_(w)/M_(n) of less than about 1.25 and a ratio of M_(z) /M_(w) of less thanabout 1.2.
 27. The composition of matter according to claim 25 whereinsaid intermolecular compositional dispersity of said copolymer (i)(a) issuch that 95 weight % of said copolymer chains have a composition 13weight % or less different from said average ethylene composition. 28.The composition of matter according to claim 23 wherein said lowcrystallinity segment of said copolymer (i)(a) comprises from about 30to 50 weight % ethylene.
 29. The composition of matter according toclaim 1 wherein said copolymer (i)(a) has a total minimum ethylenecontent of about 20 % on a weight basis.
 30. The composition of matteraccording to claim 1 wherein said copolymer's (i)(a) chain segmentsequences are characterized by at least one of the structures:

    M-T                                                        (I)

    T.sup.1 -(M-T.sup.2).sub.x                                 (II)

    T.sup.1 -(M.sup.1 -T.sup.2).sub.y -M.sup.2                 (III)

wherein x and y are each integers of 1 to 3, M comprises saidcrystallizable segment, T comprises said low crystallinity segment, M¹and M² are the same or different and each comprises an M segment, and T¹and T² are the same or different and each comprises a T segment.
 31. Thecomposition of matter according to claim 30 wherein said copolymer's(i)(a) segment sequences are characterized by structure I.
 32. Thecomposition of matter according to claim 30 wherein said copolymer's(i)(a) chain segment sequences are characterized by structure II. 33.The composition of matter according to claim 22 wherein x is one. 34.The composition of matter according to claim 33 in said copolymer (i)(a)said T¹ and T² segments are of substantially the same weight-averagemolecular weight.
 35. The composition of matter according to claim 34wherein in said copolymer (i)(a) the sum of the weight average molecularweights of said T¹ and T² segments is substantially equal to theweight-average molecular weight of said M segment.
 36. The compositionof matter according to claim 32 wherein said copolymer (i)(a) has a MWDcharacterized by at least one of a ratio of M_(w) /M_(w) of less thanabout 1.5 and a ratio of M_(z) /M_(w) of less than about 1.5.
 37. Thecomposition of matter according to claim 35 wherein said copolymer(i)(a) has a MWD characterized by at least one of a ratio of M_(w)/M_(n) of less than about 1.25 and a ratio of M_(z) /M_(w) of less thanabout 1.2.
 38. An oleaginous composition comprising:(1) oleaginousmaterial and (2) a viscosity index improving effective amount of amultifunctional viscosity index improver comprised of reaction productof(i) (a) from 1 to 5 moles of a copolymer of ethylene and at least oneother alpha-olefin monomer, said copolymer comprising intramolecularlyheterogeneous copolymer chains containing at least one crystallinityethylene-alpha-olefin copolymer segment, wherein said at least onecrystallizable segment comprises at least about 10 weight percent ofsaid copolymer chain and contains at least about 57 weight percentethylene, wherein said low crystallinity segment contains not greaterthan about 53 weight percent ethylene, and wherein said copolymer has amolecular weight distribution characterized by at least one of a ratioof M_(w) /M_(n) of less than 2 and a ratio of M_(z) /M_(w) of less than1.8, and wherein at least two portions of an individual intramolecularlyheterogeneous chain, each portion comprising at least 5 weight percentof said chain, differ in composition from one another by at least 7weight percent ethylene, said copolymer grafted with (b) from about 0.7to 4.0 moles of ethylenically monounsaturated carboxylic acid materialhaving 1 to 2 carboxylic acid groups or anhydride group per mole ofcopolymer to form grafted ethylene copolymer; and (ii) one moleamido-comprising reaction product (a) from about 1 to 10 equivalents ofpolyamine, based upon the primary amine content of said polyamine and(b) one mole of an alpha, beta-unsaturated compound represented by theformula ##STR32## wherein X is oxygen, Y is --OR⁴ or ##STR33## and R¹,R², R³, R⁴ and R⁵ independently selected from hydrogen, hydrocarbyl, andsubstituted hydrocarbyl.
 39. The composition according to claim 38 whichcontains viscosity index improving and dispersant effective amount of(2).
 40. The composition according to claim 39 which contains from about0.001 to about 49 wt. % of (2).
 41. The composition according to claim39 which contains from about 0.001 to about 20 wt. % of (2).
 42. Thecomposition according to claim 41 which contains from about 0.01 toabout 15 wt. % of (2).
 43. The composition according to claim 42 whichcontains from about 0.1 to about 10 wt. % of (2).
 44. The compositionaccording to claim 38 wherein (1) is a lubricating oil.
 45. Thecomposition according to claim 44 wherein said composition is a fullyformulated lubricating oil composition.
 46. The composition according toclaim 44 wherein said composition is an oil concentrate.
 47. Thecomposition according to claim 35 wherein said copolymer of ethylene(2)(i)(a) comprises copolymer of ethylene and propylene.
 48. Thecomposition according to claim 38, wherein said copolymer (2)(i)(a) hasan intermolecular compositional dispersity such that 95 weight % of saidcopolymer chains have a composition 15 weight % or less different fromsaid average ethylene composition.
 49. The composition according toclaim 48 wherein said intermolecular compositional dispersity of saidcopolymer (2)(i)(a) is such that 95 weight % of said copolymer chainshave a composition 10 wt. % or less different from said average ethylenecomposition.
 50. The composition according to claim 38 wherein said lowcrystallinity segment of said copolymer (2)(i)(a) comprises from about20 to 53 wt. % ethylene.
 51. The composition according to claim 50wherein said crystallizable segment of said copolymer (2)i)(a) comprisesat least about 57 wt. % ethylene.
 52. The composition according to claim38 wherein said copolymer (2)(i)(a) is characterized by a weight-averagemolecular weight of from about 20,000 to about 250,000.
 53. Thecomposition according to claim 38 wherein said copolymer (2)(i)(a) has aMWD characterized by at least one of a ratio of M_(w) /M_(n) of lessthan about 1.5 and a ratio of M_(z) /M_(w) of less than about 1.5. 54.The composition according to claim 53 wherein said copolymer (2)(i)(a)has a MWD characterized by at least one of a ratio of M_(w) /M_(n) ofless than about 1.25 and a ratio of M_(z) /M_(w) of less than about 1.2.55. The composition according to claim 53 wherein said intermolecularcompositional dispersity of said copolymer (2)(i)(a) is such that 95weight % of said copolymer chains have a composition 13 weight % or lessdifferent from said average ethylene composition.
 56. The compositionaccording to claim 50 wherein said low crystallinity segment of saidcopolymer (2)(i)(a) comprises from about 30 to 50 weight % ethylene. 57.The composition according to claim 38 wherein said copolymer (2)(i)(a)has a total minimum ethylene content of about 20 % on a weight basis.58. The composition according to claim 38 wherein said copolymer's(2)(i)(a) chain segment sequences are characterized by at least one ofthe structures:

    M-T                                                        (I)

    T.sup.1 -(M-T.sup.2).sub.x                                 (II)

    T.sup.1 -(M.sup.1 -M.sup.1 -T.sup.2).sub.y -M.sup.2        (III)

wherein x and y are each integers of 1 to 3, M comprises saidcrystallizable segment, T comprises said low crystallinity segment, M¹and M² are the same or different and each comprises an M segment, and T¹and T² are the same or different and each comprises a T segment.
 59. Thecomposition according to claim 58 wherein said copolymer's (2)(i)(a)segment sequences are characterized by structure I.
 60. The compositionaccording to claim 59 wherein said copolymer's (2)(i)(a) chain segmentsequences are characterized by structure II.
 61. The compositionaccording to claim 60 wherein x is one.
 62. The composition according toclaim 61 wherein in said copolymer (2)(i)(a) said T¹ and T² segments areof substantially the same weight-average molecular weight.
 63. Thecomposition according to claim 62 wherein in said copolymer (2)(i)(a)the sum of the weight average molecular weights of said T¹ and T²segments is substantially equal to the weight-average molecular weightof said M segment.
 64. The composition according to claim 63 whereinsaid copolymer (2)(i)(a) has a MWD characterized by at least one of aratio of M_(w) /M_(n) of less than about 1.5 and a ratio of M_(z) /M_(w)of less than about 1.5.
 65. The composition according to claim 64wherein said copolymer (2)(i)(a) has a MWD characterized by at least oneor a ratio of M_(w) /M_(n) of less than about 1.25 and a ratio of M_(z)/M_(w) of less than about 1.2.
 66. The composition according to claim 65wherein said copolymer (2)(i)(a) has a MWD characterized by both a ratioof M_(w) /M_(n) of less than about 1.25 and a ratio of M_(z) /M_(w) ofless than about 1.2.
 67. The composition according to claim 38 whereinsaid copolymer (2)(i)(a) has a total ethylene content of greater thanabout 35% on a weight basis.
 68. The composition according to claim 38wherein (2)(i)(b) is selected from C₃ to C₁₀ monounsaturatedmonocarboxylic acids.
 69. The composition according to claim 38 wherein(2)(i)(b) is selected from C₄ to C₁₀ monounsaturated dicarboxylic acidsor anhydrides.
 70. The composition according to claim 69 wherein(2)(i)(b) is selected from the group consisting of maleic acid, maleicanhydride, and mixtures thereof.
 71. The composition according to claim70 wherein (2)(i)(b1 is maleic anhydride.
 72. The composition accordingto claim 70 wherein said copolymer of ethylene (2)(i)(a) comprisescopolymer of ethylene and propylene.
 73. The composition according toclaim 68 wherein (2)(i)(b) is selected from the group consisting ofacrylic acid or esters thereof and methacrylic acid or esters thereof.74. The composition according to claim 72 wherein said polyamine(2)(ii)(a) contains from 2 to about 60 carbon atoms and from 2 to about12 nitrogen atoms per molecule.
 75. The composition according to claim74 wherein said polyamine (2)(ii)(a) comprises alkylenepolyamine orpolyalkylenepolyamine wherein each alkylene group contains 2 to 6carbons and said alkylenepolyamine or polyalkylenepolyamine containsfrom 2 to about 5 nitrogen atoms per molecule.
 76. The compositionaccording to claim 74 wherein said polyamine (2)(ii)(a) contains atleast two primary amino groups per molecule.
 77. The compositionaccording to claim 75 wherein said alkylenepolyamine orpolyalkylenepolyamine contains at least two primary amino groups permolecule.
 78. The composition according to claim 77 wherein p saidpolyalkylenepolyamine comprises polyethylenepolyamine orpolypropylenepolyamine.
 79. The composition according to claim 72wherein said polyamine (2)(ii)(a) contains an average of at least 2primary nitrogen atoms per molecule, and said polyamine and said alpha,beta-unsaturated compound are contacted in an amount of from about 3 to5 equivalents of said polyamine, based on said primary amine content,per mole of said alpha, beta-unsaturated compound.
 80. The compositionaccording to claim 38 wherein said polyamine (2)(ii)(a) contains from 2to about 60 carbon atoms and from 2 to about 12 nitrogen atoms permolecule.
 81. The composition according to claim 80 wherein saidpolyamine (2)(ii)(a) comprises alkylenepolyamine orpolyalkylenepolyamine wherein each alkylene group contains 2 to 6carbons and said alkylenepolyamine or polyalkylenepolyamine containsfrom 2 to about 5 nitrogen atoms per molecule.
 82. The compositionaccording to claim 80 wherein polyamine (2)(ii)(a) contains at least twoprimary amino groups per molecule.
 83. The composition according toclaim 81 wherein said alkylenepolyamine or polyalkylenepolyaminecontains at least two primary amino groups per molecule.
 84. Thecomposition according to claim 83 wherein said polyalkylenepolyaminecomprises polyethylenepolyamine or polypropylenepolyamine.
 85. Thecomposition according to claim 38 wherein said polyamine (2)(ii)(a)contains an average of at least 2 primary nitrogen atoms per molecule,and said polyamine and said alpha, beta-unsaturated compound arecontacted in an amount of from about 3 to 5 equivalents of saidpolyamine, based on said primary amine content, per mole of said alpha,beta-unsaturated compound.